在Jquery的HTML页面上的第4段之后出现链接
[英]Having a link appear after the 4th paragraph on an HTML page in Jquery
问题描述
所以我在一个JavaScript / Jquery类中，对于当前的工作，我需要在文章的第四段之后插入一个返回顶部的链接。 我似乎这是选择特定段落的一种方式：
$("p").eq(1).css("background-color", "yellow");
我需要弄清楚如何与现有的Jquery一起使用：
// Add "back to top" links.
$('<a href="#top">back to top</a>').insertAfter('article.chapter p');
$('<a id="top"></a>').prependTo('body');
我的想法是这样做：
// Add "back to top" links.
$('<a href="#top">back to top</a>').insertAfter("article.chapter p").eq(3).
$('<a id="top"></a>').prependTo('body');
那是行不通的，我今天早些时候才了解这种技术。 做这个的最好方式是什么。
这是HTML：
<!DOCTYPE html>
<!--Lisa Hergert's Assignment 6-->
<html lang="en">
<head>
<meta charset="utf-8">
<title>Flatland</title>
<link rel="stylesheet" href="05.css" type="text/css" />
<script src="jquery.js"></script>
<script src="complete.js"></script>
<script src="prep.js"></script>
</head>
<body>
<main id="container">
<h1 id="f-title">Flatland: A Romance of Many Dimensions</h1>
<p id="f-author">by Edwin A. Abbott</p>
<h2>Part 1, Section 3</h2>
<h3 id="f-subtitle">Concerning the Inhabitants of Flatland</h3>
<p id="excerpt">an excerpt</p>
<article class="chapter">
<p class="square">Our Professional Men and Gentlemen are Squares (to which class I myself belong) and Five-Sided Figures or <a href="http://en.wikipedia.org/wiki/Pentagon">Pentagons</a>.</p>
<p class="nobility hexagon">Next above these come the Nobility, of whom there are several degrees, beginning at Six-Sided Figures, or <a href="http://en.wikipedia.org/wiki/Hexagon">Hexagons</a>, and from thence rising in the number of their sides till they receive the honourable title of <a href="http://en.wikipedia.org/wiki/Polygon">Polygonal</a>, or many-Sided. Finally when the number of the sides becomes so numerous, and the sides themselves so small, that the figure cannot be distinguished from a <a href="http://en.wikipedia.org/wiki/Circle">circle</a>, he is included in the Circular or Priestly order; and this is the highest class of all.</p>
<p><span class="pull-quote">It is a Law of Nature <span class="drop">with us</span> that a male child shall have <strong>one more side</strong> than his father</span>, so that each generation shall rise (as a rule) one step in the scale of development and nobility. Thus the son of a Square is a Pentagon; the son of a Pentagon, a Hexagon; and so on.</p>
<p>But this rule applies not always to the Tradesman, and still less often to the Soldiers, and to the Workmen; who indeed can hardly be said to deserve the name of human Figures, since they have not all their sides equal. With them therefore the Law of Nature does not hold; and the son of an Isosceles (i.e. a Triangle with two sides equal) remains Isosceles still. Nevertheless, all hope is not such out, even from the Isosceles, that his posterity may ultimately rise above his degraded condition.…</p>
<p>Rarely—in proportion to the vast numbers of Isosceles births—is a genuine and certifiable Equal-Sided Triangle produced from Isosceles parents. <span class="footnote">"What need of a certificate?" a Spaceland critic may ask: "Is not the procreation of a Square Son a certificate from Nature herself, proving the Equal-sidedness of the Father?" I reply that no Lady of any position will marry an uncertified Triangle. Square offspring has sometimes resulted from a slightly Irregular Triangle; but in almost every such case the Irregularity of the first generation is visited on the third; which either fails to attain the Pentagonal rank, or relapses to the Triangular.</span> Such a birth requires, as its antecedents, not only a series of carefully arranged intermarriages, but also a long-continued exercise of frugality and self-control on the part of the would-be ancestors of the coming Equilateral, and a patient, systematic, and continuous development of the Isosceles intellect through many generations.</p>
<p><span class="pull-quote">The birth of a True Equilateral Triangle from Isosceles parents is the subject of rejoicing in our country <span class="drop">for many furlongs round</span>.</span> After a strict examination conducted by the Sanitary and Social Board, the infant, if certified as Regular, is with solemn ceremonial admitted into the class of Equilaterals. He is then immediately taken from his proud yet sorrowing parents and adopted by some childless Equilateral. <span class="footnote">The Equilateral is bound by oath never to permit the child henceforth to enter his former home or so much as to look upon his relations again, for fear lest the freshly developed organism may, by force of unconscious imitation, fall back again into his hereditary level.</span></p>
<p>How admirable is the Law of Compensation! <span class="footnote">And how perfect a proof of the natural fitness and, I may almost say, the divine origin of the aristocratic constitution of the States of Flatland!</span> By a judicious use of this Law of Nature, the Polygons and Circles are almost always able to stifle sedition in its very cradle, taking advantage of the irrepressible and boundless hopefulness of the human mind.…</p>
<p>Then the wretched rabble of the Isosceles, planless and leaderless, are ether transfixed without resistance by the small body of their brethren whom the Chief Circle keeps in pay for emergencies of this kind; or else more often, by means of jealousies and suspicious skillfully fomented among them by the Circular party, they are stirred to mutual warfare, and perish by one another's angles. No less than one hundred and twenty rebellions are recorded in our annals, besides minor outbreaks numbered at two hundred and thirty-five; and they have all ended thus.</p>
</article>
<footer id="footer">
<p>Read the <a href="http://web.archive.org/web/20050208012252/http://www.ibiblio.org/eldritch/eaa/FL.HTM">complete text of <i>Flatland</i></a>.</p>
</footer>
</main>
</body>
</html>
单击时，我还需要加粗作者的姓名，然后再次单击时，将其删除。
这就是我所拥有的，只有一半有效：
// Clicking on authors name makes it bold
$("#f-author").one ("click", function() {
$(this).wrap("<b id = 'bold'></b>");
});
$("#bold").one ("dblclick", function() {
$(this).remove();
});
谢谢。
一件事让我感到困惑，我需要在不使用addClass（）调用的情况下，将“居民”类添加到本章的所有段落中。 我研究了几种选择，最有效的选择是，但使HTML凌乱的是，用该类的新段落元素包装所有段落。 我不知道该用什么，因为有些段落已经有一个类，需要坚持下去。
2 个解决方案
解决方案1
1 2018-06-02 05:50:27
您需要使用insertAfter("article.chapter p:eq(3)")以便选择第四个p 。 注意insertAfter内部的伪类:eq(3) ，它将仅从段落列表中选择第四段。
另外，如果您想在每个四个段落之后添加链接，则需要遍历各个段落并动态设置:eq() 。
var i = 4; var elem = $('article.chapter p'); $('<a id="top"></a>').prependTo('body'); while(i<=elem.length){ $('<a href="#top">back to top</a>').insertAfter("article.chapter p:eq("+(i-1)+")"); i+=4; }
<script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.1/jquery.min.js"></script> <article class="chapter"> <p class="square">Our Professional Men and Gentlemen are Squares (to which class I myself belong) and Five-Sided Figures or <a href="http://en.wikipedia.org/wiki/Pentagon">Pentagons</a>.</p> <p class="nobility hexagon">Next above these come the Nobility, of whom there are several degrees, beginning at Six-Sided Figures, or <a href="http://en.wikipedia.org/wiki/Hexagon">Hexagons</a>, and from thence rising in the number of their sides till they receive the honourable title of <a href="http://en.wikipedia.org/wiki/Polygon">Polygonal</a>, or many-Sided. Finally when the number of the sides becomes so numerous, and the sides themselves so small, that the figure cannot be distinguished from a <a href="http://en.wikipedia.org/wiki/Circle">circle</a>, he is included in the Circular or Priestly order; and this is the highest class of all.</p> <p><span class="pull-quote">It is a Law of Nature <span class="drop">with us</span> that a male child shall have <strong>one more side</strong> than his father</span>, so that each generation shall rise (as a rule) one step in the scale of development and nobility. Thus the son of a Square is a Pentagon; the son of a Pentagon, a Hexagon; and so on.</p> <p>But this rule applies not always to the Tradesman, and still less often to the Soldiers, and to the Workmen; who indeed can hardly be said to deserve the name of human Figures, since they have not all their sides equal. With them therefore the Law of Nature does not hold; and the son of an Isosceles (ie a Triangle with two sides equal) remains Isosceles still. Nevertheless, all hope is not such out, even from the Isosceles, that his posterity may ultimately rise above his degraded condition.…</p> <p>Rarely—in proportion to the vast numbers of Isosceles births—is a genuine and certifiable Equal-Sided Triangle produced from Isosceles parents. <span class="footnote">"What need of a certificate?" a Spaceland critic may ask: "Is not the procreation of a Square Son a certificate from Nature herself, proving the Equal-sidedness of the Father?" I reply that no Lady of any position will marry an uncertified Triangle. Square offspring has sometimes resulted from a slightly Irregular Triangle; but in almost every such case the Irregularity of the first generation is visited on the third; which either fails to attain the Pentagonal rank, or relapses to the Triangular.</span> Such a birth requires, as its antecedents, not only a series of carefully arranged intermarriages, but also a long-continued exercise of frugality and self-control on the part of the would-be ancestors of the coming Equilateral, and a patient, systematic, and continuous development of the Isosceles intellect through many generations.</p> <p><span class="pull-quote">The birth of a True Equilateral Triangle from Isosceles parents is the subject of rejoicing in our country <span class="drop">for many furlongs round</span>.</span> After a strict examination conducted by the Sanitary and Social Board, the infant, if certified as Regular, is with solemn ceremonial admitted into the class of Equilaterals. He is then immediately taken from his proud yet sorrowing parents and adopted by some childless Equilateral. <span class="footnote">The Equilateral is bound by oath never to permit the child henceforth to enter his former home or so much as to look upon his relations again, for fear lest the freshly developed organism may, by force of unconscious imitation, fall back again into his hereditary level.</span></p> <p>How admirable is the Law of Compensation! <span class="footnote">And how perfect a proof of the natural fitness and, I may almost say, the divine origin of the aristocratic constitution of the States of Flatland!</span> By a judicious use of this Law of Nature, the Polygons and Circles are almost always able to stifle sedition in its very cradle, taking advantage of the irrepressible and boundless hopefulness of the human mind.…</p> <p>Then the wretched rabble of the Isosceles, planless and leaderless, are ether transfixed without resistance by the small body of their brethren whom the Chief Circle keeps in pay for emergencies of this kind; or else more often, by means of jealousies and suspicious skillfully fomented among them by the Circular party, they are stirred to mutual warfare, and perish by one another's angles. No less than one hundred and twenty rebellions are recorded in our annals, besides minor outbreaks numbered at two hundred and thirty-five; and they have all ended thus.</p> <p> that a male child shall have <strong>one more side</strong> than his father so that each generation shall rise (as a rule) one step in the scale of development and nobility. Thus the son of a Square is a Pentagon; the son of a Pentagon, a Hexagon; and so on.</p> <p>But this rule applies not always to the Tradesman, and still less often to the Soldiers, and to the Workmen; who indeed can hardly be said to deserve the name of human Figures, since they have not all their sides equal. With them therefore the Law of Nature does not hold; and the son of an Isosceles (ie a Triangle with two sides equal) remains Isosceles still. Nevertheless, all hope is not such out, even from the Isosceles, that his posterity may ultimately rise above his degraded condition.…</p> <p>Rarely—in proportion to the vast numbers of Isosceles births—is a genuine and certifiable Equal-Sided Triangle produced from Isosceles parents. <span class="footnote">"What need of a certificate?" a Spaceland critic may ask: "Is not the procreation of a Square Son a certificate from Nature herself, proving the Equal-sidedness of the Father?" I reply that no Lady of any position will marry an uncertified Triangle. Square offspring has sometimes resulted from a slightly Irregular Triangle; but in almost every such case the Irregularity of the first generation is visited on the third; which either fails to attain the Pentagonal rank, or relapses to the Triangular.</span> Such a birth requires, as its antecedents, not only a series of carefully arranged intermarriages, but also a long-continued exercise of frugality and self-control on the part of the would-be ancestors of the coming Equilateral, and a patient, systematic, and continuous development of the Isosceles intellect through many generations.</p> <p><span class="pull-quote">The birth of a True Equilateral Triangle from Isosceles parents is the subject of rejoicing in our country <span class="drop">for many furlongs round</span>.</span> After a strict examination conducted by the Sanitary and Social Board, the infant, if certified as Regular, is with solemn ceremonial admitted into the class of Equilaterals. He is then immediately taken from his proud yet sorrowing parents and adopted by some childless Equilateral. <span class="footnote">The Equilateral is bound by oath never to permit the child henceforth to enter his former home or so much as to look upon his relations again, for fear lest the freshly developed organism may, by force of unconscious imitation, fall back again into his hereditary level.</span></p> <p> that a male child shall have <strong>one more side</strong> than his father so that each generation shall rise (as a rule) one step in the scale of development and nobility. Thus the son of a Square is a Pentagon; the son of a Pentagon, a Hexagon; and so on.</p> <p>But this rule applies not always to the Tradesman, and still less often to the Soldiers, and to the Workmen; who indeed can hardly be said to deserve the name of human Figures, since they have not all their sides equal. With them therefore the Law of Nature does not hold; and the son of an Isosceles (ie a Triangle with two sides equal) remains Isosceles still. Nevertheless, all hope is not such out, even from the Isosceles, that his posterity may ultimately rise above his degraded condition.…</p> <p>Rarely—in proportion to the vast numbers of Isosceles births—is a genuine and certifiable Equal-Sided Triangle produced from Isosceles parents. <span class="footnote">"What need of a certificate?" a Spaceland critic may ask: "Is not the procreation of a Square Son a certificate from Nature herself, proving the Equal-sidedness of the Father?" I reply that no Lady of any position will marry an uncertified Triangle. Square offspring has sometimes resulted from a slightly Irregular Triangle; but in almost every such case the Irregularity of the first generation is visited on the third; which either fails to attain the Pentagonal rank, or relapses to the Triangular.</span> Such a birth requires, as its antecedents, not only a series of carefully arranged intermarriages, but also a long-continued exercise of frugality and self-control on the part of the would-be ancestors of the coming Equilateral, and a patient, systematic, and continuous development of the Isosceles intellect through many generations.</p> <p><span class="pull-quote">The birth of a True Equilateral Triangle from Isosceles parents is the subject of rejoicing in our country <span class="drop">for many furlongs round</span>.</span> After a strict examination conducted by the Sanitary and Social Board, the infant, if certified as Regular, is with solemn ceremonial admitted into the class of Equilaterals. He is then immediately taken from his proud yet sorrowing parents and adopted by some childless Equilateral. <span class="footnote">The Equilateral is bound by oath never to permit the child henceforth to enter his former home or so much as to look upon his relations again, for fear lest the freshly developed organism may, by force of unconscious imitation, fall back again into his hereditary level.</span></p> <p> that a male child shall have <strong>one more side</strong> than his father so that each generation shall rise (as a rule) one step in the scale of development and nobility. Thus the son of a Square is a Pentagon; the son of a Pentagon, a Hexagon; and so on.</p> <p>But this rule applies not always to the Tradesman, and still less often to the Soldiers, and to the Workmen; who indeed can hardly be said to deserve the name of human Figures, since they have not all their sides equal. With them therefore the Law of Nature does not hold; and the son of an Isosceles (ie a Triangle with two sides equal) remains Isosceles still. Nevertheless, all hope is not such out, even from the Isosceles, that his posterity may ultimately rise above his degraded condition.…</p> <p>Rarely—in proportion to the vast numbers of Isosceles births—is a genuine and certifiable Equal-Sided Triangle produced from Isosceles parents. <span class="footnote">"What need of a certificate?" a Spaceland critic may ask: "Is not the procreation of a Square Son a certificate from Nature herself, proving the Equal-sidedness of the Father?" I reply that no Lady of any position will marry an uncertified Triangle. Square offspring has sometimes resulted from a slightly Irregular Triangle; but in almost every such case the Irregularity of the first generation is visited on the third; which either fails to attain the Pentagonal rank, or relapses to the Triangular.</span> Such a birth requires, as its antecedents, not only a series of carefully arranged intermarriages, but also a long-continued exercise of frugality and self-control on the part of the would-be ancestors of the coming Equilateral, and a patient, systematic, and continuous development of the Isosceles intellect through many generations.</p> <p><span class="pull-quote">The birth of a True Equilateral Triangle from Isosceles parents is the subject of rejoicing in our country <span class="drop">for many furlongs round</span>.</span> After a strict examination conducted by the Sanitary and Social Board, the infant, if certified as Regular, is with solemn ceremonial admitted into the class of Equilaterals. He is then immediately taken from his proud yet sorrowing parents and adopted by some childless Equilateral. <span class="footnote">The Equilateral is bound by oath never to permit the child henceforth to enter his former home or so much as to look upon his relations again, for fear lest the freshly developed organism may, by force of unconscious imitation, fall back again into his hereditary level.</span></p> </article> <footer id="footer"> <p>Read the <a href="http://web.archive.org/web/20050208012252/http://www.ibiblio.org/eldritch/eaa/FL.HTM">complete text of <i>Flatland</i></a>.</p> </footer>
解决方案2
1 已采纳 2018-06-02 06:16:17
添加“返回页首”链接：
如果您需要在第4段之后及其后的每个段落，请使用:gt()选择器 ：
insertAfter('article.chapter p:gt(2)');
$('<a href="#top">back to top</a>').insertAfter('article.chapter p:gt(2)');
<script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.1/jquery.min.js"></script> <article class="chapter"> <p class="square">Our Professional Men and Gentlemen are Squares (to which class I myself belong) and Five-Sided Figures or <a href="http://en.wikipedia.org/wiki/Pentagon">Pentagons</a>.</p> <p class="nobility hexagon">Next above these come the Nobility, of whom there are several degrees, beginning at Six-Sided Figures, or <a href="http://en.wikipedia.org/wiki/Hexagon">Hexagons</a>, and from thence rising in the number of their sides till they receive the honourable title of <a href="http://en.wikipedia.org/wiki/Polygon">Polygonal</a>, or many-Sided. Finally when the number of the sides becomes so numerous, and the sides themselves so small, that the figure cannot be distinguished from a <a href="http://en.wikipedia.org/wiki/Circle">circle</a>, he is included in the Circular or Priestly order; and this is the highest class of all.</p> <p><span class="pull-quote">It is a Law of Nature <span class="drop">with us</span> that a male child shall have <strong>one more side</strong> than his father</span>, so that each generation shall rise (as a rule) one step in the scale of development and nobility. Thus the son of a Square is a Pentagon; the son of a Pentagon, a Hexagon; and so on.</p> <p>But this rule applies not always to the Tradesman, and still less often to the Soldiers, and to the Workmen; who indeed can hardly be said to deserve the name of human Figures, since they have not all their sides equal. With them therefore the Law of Nature does not hold; and the son of an Isosceles (ie a Triangle with two sides equal) remains Isosceles still. Nevertheless, all hope is not such out, even from the Isosceles, that his posterity may ultimately rise above his degraded condition.…</p> <p>Rarely—in proportion to the vast numbers of Isosceles births—is a genuine and certifiable Equal-Sided Triangle produced from Isosceles parents. <span class="footnote">"What need of a certificate?" a Spaceland critic may ask: "Is not the procreation of a Square Son a certificate from Nature herself, proving the Equal-sidedness of the Father?" I reply that no Lady of any position will marry an uncertified Triangle. Square offspring has sometimes resulted from a slightly Irregular Triangle; but in almost every such case the Irregularity of the first generation is visited on the third; which either fails to attain the Pentagonal rank, or relapses to the Triangular.</span> Such a birth requires, as its antecedents, not only a series of carefully arranged intermarriages, but also a long-continued exercise of frugality and self-control on the part of the would-be ancestors of the coming Equilateral, and a patient, systematic, and continuous development of the Isosceles intellect through many generations.</p> <p><span class="pull-quote">The birth of a True Equilateral Triangle from Isosceles parents is the subject of rejoicing in our country <span class="drop">for many furlongs round</span>.</span> After a strict examination conducted by the Sanitary and Social Board, the infant, if certified as Regular, is with solemn ceremonial admitted into the class of Equilaterals. He is then immediately taken from his proud yet sorrowing parents and adopted by some childless Equilateral. <span class="footnote">The Equilateral is bound by oath never to permit the child henceforth to enter his former home or so much as to look upon his relations again, for fear lest the freshly developed organism may, by force of unconscious imitation, fall back again into his hereditary level.</span></p> <p>How admirable is the Law of Compensation! <span class="footnote">And how perfect a proof of the natural fitness and, I may almost say, the divine origin of the aristocratic constitution of the States of Flatland!</span> By a judicious use of this Law of Nature, the Polygons and Circles are almost always able to stifle sedition in its very cradle, taking advantage of the irrepressible and boundless hopefulness of the human mind.…</p> <p>Then the wretched rabble of the Isosceles, planless and leaderless, are ether transfixed without resistance by the small body of their brethren whom the Chief Circle keeps in pay for emergencies of this kind; or else more often, by means of jealousies and suspicious skillfully fomented among them by the Circular party, they are stirred to mutual warfare, and perish by one another's angles. No less than one hundred and twenty rebellions are recorded in our annals, besides minor outbreaks numbered at two hundred and thirty-five; and they have all ended thus.</p> </article>
如果在每第4段之后需要它，请使用:nth-child()选择器 ：
insertAfter('article.chapter p:nth-child(4n)');
$('<a href="#top">back to top</a>').insertAfter('article.chapter p:nth-child(4n)');
<script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.1/jquery.min.js"></script> <article class="chapter"> <p class="square">Our Professional Men and Gentlemen are Squares (to which class I myself belong) and Five-Sided Figures or <a href="http://en.wikipedia.org/wiki/Pentagon">Pentagons</a>.</p> <p class="nobility hexagon">Next above these come the Nobility, of whom there are several degrees, beginning at Six-Sided Figures, or <a href="http://en.wikipedia.org/wiki/Hexagon">Hexagons</a>, and from thence rising in the number of their sides till they receive the honourable title of <a href="http://en.wikipedia.org/wiki/Polygon">Polygonal</a>, or many-Sided. Finally when the number of the sides becomes so numerous, and the sides themselves so small, that the figure cannot be distinguished from a <a href="http://en.wikipedia.org/wiki/Circle">circle</a>, he is included in the Circular or Priestly order; and this is the highest class of all.</p> <p><span class="pull-quote">It is a Law of Nature <span class="drop">with us</span> that a male child shall have <strong>one more side</strong> than his father</span>, so that each generation shall rise (as a rule) one step in the scale of development and nobility. Thus the son of a Square is a Pentagon; the son of a Pentagon, a Hexagon; and so on.</p> <p>But this rule applies not always to the Tradesman, and still less often to the Soldiers, and to the Workmen; who indeed can hardly be said to deserve the name of human Figures, since they have not all their sides equal. With them therefore the Law of Nature does not hold; and the son of an Isosceles (ie a Triangle with two sides equal) remains Isosceles still. Nevertheless, all hope is not such out, even from the Isosceles, that his posterity may ultimately rise above his degraded condition.…</p> <p>Rarely—in proportion to the vast numbers of Isosceles births—is a genuine and certifiable Equal-Sided Triangle produced from Isosceles parents. <span class="footnote">"What need of a certificate?" a Spaceland critic may ask: "Is not the procreation of a Square Son a certificate from Nature herself, proving the Equal-sidedness of the Father?" I reply that no Lady of any position will marry an uncertified Triangle. Square offspring has sometimes resulted from a slightly Irregular Triangle; but in almost every such case the Irregularity of the first generation is visited on the third; which either fails to attain the Pentagonal rank, or relapses to the Triangular.</span> Such a birth requires, as its antecedents, not only a series of carefully arranged intermarriages, but also a long-continued exercise of frugality and self-control on the part of the would-be ancestors of the coming Equilateral, and a patient, systematic, and continuous development of the Isosceles intellect through many generations.</p> <p><span class="pull-quote">The birth of a True Equilateral Triangle from Isosceles parents is the subject of rejoicing in our country <span class="drop">for many furlongs round</span>.</span> After a strict examination conducted by the Sanitary and Social Board, the infant, if certified as Regular, is with solemn ceremonial admitted into the class of Equilaterals. He is then immediately taken from his proud yet sorrowing parents and adopted by some childless Equilateral. <span class="footnote">The Equilateral is bound by oath never to permit the child henceforth to enter his former home or so much as to look upon his relations again, for fear lest the freshly developed organism may, by force of unconscious imitation, fall back again into his hereditary level.</span></p> <p>How admirable is the Law of Compensation! <span class="footnote">And how perfect a proof of the natural fitness and, I may almost say, the divine origin of the aristocratic constitution of the States of Flatland!</span> By a judicious use of this Law of Nature, the Polygons and Circles are almost always able to stifle sedition in its very cradle, taking advantage of the irrepressible and boundless hopefulness of the human mind.…</p> <p>Then the wretched rabble of the Isosceles, planless and leaderless, are ether transfixed without resistance by the small body of their brethren whom the Chief Circle keeps in pay for emergencies of this kind; or else more often, by means of jealousies and suspicious skillfully fomented among them by the Circular party, they are stirred to mutual warfare, and perish by one another's angles. No less than one hundred and twenty rebellions are recorded in our annals, besides minor outbreaks numbered at two hundred and thirty-five; and they have all ended thus.</p> </article>
如果需要在第4段之后（仅第4段）使用它 ，请使用:eq()选择器 ：
insertAfter('article.chapter p:eq(3)');
$('<a href="#top">back to top</a>').insertAfter('article.chapter p:eq(3)');
<script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.1/jquery.min.js"></script> <article class="chapter"> <p class="square">Our Professional Men and Gentlemen are Squares (to which class I myself belong) and Five-Sided Figures or <a href="http://en.wikipedia.org/wiki/Pentagon">Pentagons</a>.</p> <p class="nobility hexagon">Next above these come the Nobility, of whom there are several degrees, beginning at Six-Sided Figures, or <a href="http://en.wikipedia.org/wiki/Hexagon">Hexagons</a>, and from thence rising in the number of their sides till they receive the honourable title of <a href="http://en.wikipedia.org/wiki/Polygon">Polygonal</a>, or many-Sided. Finally when the number of the sides becomes so numerous, and the sides themselves so small, that the figure cannot be distinguished from a <a href="http://en.wikipedia.org/wiki/Circle">circle</a>, he is included in the Circular or Priestly order; and this is the highest class of all.</p> <p><span class="pull-quote">It is a Law of Nature <span class="drop">with us</span> that a male child shall have <strong>one more side</strong> than his father</span>, so that each generation shall rise (as a rule) one step in the scale of development and nobility. Thus the son of a Square is a Pentagon; the son of a Pentagon, a Hexagon; and so on.</p> <p>But this rule applies not always to the Tradesman, and still less often to the Soldiers, and to the Workmen; who indeed can hardly be said to deserve the name of human Figures, since they have not all their sides equal. With them therefore the Law of Nature does not hold; and the son of an Isosceles (ie a Triangle with two sides equal) remains Isosceles still. Nevertheless, all hope is not such out, even from the Isosceles, that his posterity may ultimately rise above his degraded condition.…</p> <p>Rarely—in proportion to the vast numbers of Isosceles births—is a genuine and certifiable Equal-Sided Triangle produced from Isosceles parents. <span class="footnote">"What need of a certificate?" a Spaceland critic may ask: "Is not the procreation of a Square Son a certificate from Nature herself, proving the Equal-sidedness of the Father?" I reply that no Lady of any position will marry an uncertified Triangle. Square offspring has sometimes resulted from a slightly Irregular Triangle; but in almost every such case the Irregularity of the first generation is visited on the third; which either fails to attain the Pentagonal rank, or relapses to the Triangular.</span> Such a birth requires, as its antecedents, not only a series of carefully arranged intermarriages, but also a long-continued exercise of frugality and self-control on the part of the would-be ancestors of the coming Equilateral, and a patient, systematic, and continuous development of the Isosceles intellect through many generations.</p> <p><span class="pull-quote">The birth of a True Equilateral Triangle from Isosceles parents is the subject of rejoicing in our country <span class="drop">for many furlongs round</span>.</span> After a strict examination conducted by the Sanitary and Social Board, the infant, if certified as Regular, is with solemn ceremonial admitted into the class of Equilaterals. He is then immediately taken from his proud yet sorrowing parents and adopted by some childless Equilateral. <span class="footnote">The Equilateral is bound by oath never to permit the child henceforth to enter his former home or so much as to look upon his relations again, for fear lest the freshly developed organism may, by force of unconscious imitation, fall back again into his hereditary level.</span></p> <p>How admirable is the Law of Compensation! <span class="footnote">And how perfect a proof of the natural fitness and, I may almost say, the divine origin of the aristocratic constitution of the States of Flatland!</span> By a judicious use of this Law of Nature, the Polygons and Circles are almost always able to stifle sedition in its very cradle, taking advantage of the irrepressible and boundless hopefulness of the human mind.…</p> <p>Then the wretched rabble of the Isosceles, planless and leaderless, are ether transfixed without resistance by the small body of their brethren whom the Chief Circle keeps in pay for emergencies of this kind; or else more often, by means of jealousies and suspicious skillfully fomented among them by the Circular party, they are stirred to mutual warfare, and perish by one another's angles. No less than one hundred and twenty rebellions are recorded in our annals, besides minor outbreaks numbered at two hundred and thirty-five; and they have all ended thus.</p> </article>
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<script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.1/jquery.min.js"></script> <h1 id="f-title">Flatland: A Romance of Many Dimensions</h1> <p id="f-author">by Edwin A. Abbott</p> <h2>Part 1, Section 3</h2> <h3 id="f-subtitle">Concerning the Inhabitants of Flatland</h3>
如何在使用 ajax 和 JavaScript 提交页面之前按下数字的第 4 位数字后进行验证？
[英]How can i validate after pressing 4th digits of number before page submit using ajax and JavaScript?
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[英]Jquery autocomplete only shows results after i type 4th letter on input
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