使用JavaScript提取2个字符之间的字符串

Question

我有一个看起来像这样的字符串

<iframe src="https://www.google.com/recaptcha/api2/anchor?ar=1&amp;k=6LekMVAUAAAAAPDp1Cn7YMzjZynSb9csmX5V4a9P&amp;co=aHR0cHM6Ly93d3cub21lZ2xlLmNvbTo0NDM.&amp;hl=en&amp;v=v1526884278587&amp;size=normal&amp;cb=jssxsvw1wcmm" role="presentation" scrolling="no" sandbox="allow-forms allow-popups allow-same-origin allow-scripts allow-top-navigation allow-modals allow-popups-to-escape-sandbox" style="outline: 1px solid blue;" width="304" height="78" frameborder="0"></iframe>

我希望最终输出看起来像这样

6LekMVAUAAAAAPDp1Cn7YMzjZynSb9csmX5V4a9P

基本上我想得到k=和&之间的字符串

这是我到目前为止获得的JavaScript

 var str = '<iframe src="https://www.google.com/recaptcha/api2/anchor?ar=1&amp;k=6LekMVAUAAAAAPDp1Cn7YMzjZynSb9csmX5V4a9P&amp;co=aHR0cHM6Ly93d3cub21lZ2xlLmNvbTo0NDM.&amp;hl=en&amp;v=v1526884278587&amp;size=normal&amp;cb=jssxsvw1wcmm" role="presentation" scrolling="no" sandbox="allow-forms allow-popups allow-same-origin allow-scripts allow-top-navigation allow-modals allow-popups-to-escape-sandbox" style="outline: 1px solid blue;" width="304" height="78" frameborder="0"></iframe>' var string=str.substring(str.lastIndexOf("k=")+1,str.lastIndexOf("&")); console.log(string); 

但这不是我想要的输出。 谁能帮我解决这个问题？ 我需要仅在javascript中使用正则表达式

Answer 1

以下正则表达式在k=和&之间查找字符串并捕获它。

 var str = '<iframe src="https://www.google.com/recaptcha/api2/anchor?ar=1&amp;k=6LekMVAUAAAAAPDp1Cn7YMzjZynSb9csmX5V4a9P&amp;co=aHR0cHM6Ly93d3cub21lZ2xlLmNvbTo0NDM.&amp;hl=en&amp;v=v1526884278587&amp;size=normal&amp;cb=jssxsvw1wcmm" role="presentation" scrolling="no" sandbox="allow-forms allow-popups allow-same-origin allow-scripts allow-top-navigation allow-modals allow-popups-to-escape-sandbox" style="outline: 1px solid blue;" width="304" height="78" frameborder="0"></iframe>' var string=str.match(/k=([\\w]*)&/)[1] console.log(string); 

Answer 2

您可以尝试以下方法：

 var str = '<iframe src="https://www.google.com/recaptcha/api2/anchor?ar=1&amp;k=6LekMVAUAAAAAPDp1Cn7YMzjZynSb9csmX5V4a9P&amp;co=aHR0cHM6Ly93d3cub21lZ2xlLmNvbTo0NDM.&amp;hl=en&amp;v=v1526884278587&amp;size=normal&amp;cb=jssxsvw1wcmm" role="presentation" scrolling="no" sandbox="allow-forms allow-popups allow-same-origin allow-scripts allow-top-navigation allow-modals allow-popups-to-escape-sandbox" style="outline: 1px solid blue;" width="304" height="78" frameborder="0"></iframe>' var string=str.match(/k=([^&]*)/i)[1]; console.log(string); 

Answer 3

您说您要使用正则表达式，但在问题中使用了.substring 。

所以……这是您的更正解决方案，您还不算太远：

 var str = '<iframe src="https://www.google.com/recaptcha/api2/anchor?ar=1&amp;k=6LekMVAUAAAAAPDp1Cn7YMzjZynSb9csmX5V4a9P&amp;co=aHR0cHM6Ly93d3cub21lZ2xlLmNvbTo0NDM.&amp;hl=en&amp;v=v1526884278587&amp;size=normal&amp;cb=jssxsvw1wcmm" role="presentation" scrolling="no" sandbox="allow-forms allow-popups allow-same-origin allow-scripts allow-top-navigation allow-modals allow-popups-to-escape-sandbox" style="outline: 1px solid blue;" width="304" height="78" frameborder="0"></iframe>'; var string = str.substring(str.indexOf("k=") + 2); // Substring starts after "k=" string = string.substring(0, string.indexOf("&")); // Substring stops at the first "&" console.log(string); 

请注意，我用.indexOf()来获得第一场比赛，而不是.lastIndexOf()

希望能帮助到你。

Answer 4

您尝试过的内容是正确的，但是..首先您应该知道lastIndexOf返回什么。

它将返回给定字符串的开始位置，这意味着您正在寻找“ k =“。 因此它将检查“ k =”是否存在，但将返回“ k”位置。

所以总是将字符串的长度添加到lastIndexOf返回值中。.还有一个错误是，您正在检查“＆”的最后一个索引。您可以使用indexOf（string，fromIndex）方法检查indexOf。对于给定索引中的给定字符串。

检查一下..

 var str = '<iframe src="https://www.google.com/recaptcha/api2/anchor?ar=1&amp;k=6LekMVAUAAAAAPDp1Cn7YMzjZynSb9csmX5V4a9P&amp;co=aHR0cHM6Ly93d3cub21lZ2xlLmNvbTo0NDM.&amp;hl=en&amp;v=v1526884278587&amp;size=normal&amp;cb=jssxsvw1wcmm" role="presentation" scrolling="no" sandbox="allow-forms allow-popups allow-same-origin allow-scripts allow-top-navigation allow-modals allow-popups-to-escape-sandbox" style="outline: 1px solid blue;" width="304" height="78" frameborder="0"></iframe>' var lookingFor = "k="; var fromIndex = str.lastIndexOf(lookingFor)+lookingFor.length; var string = str.substring(fromIndex, str.indexOf("&", fromIndex)); console.log(string); 

Answer 5

    var str = '<iframe src="https://www.google.com/recaptcha/api2/anchor?ar=1&amp;k=6LekMVAUAAAAAPDp1Cn7YMzjZynSb9csmX5V4a9P&amp;co=aHR0cHM6Ly93d3cub21lZ2xlLmNvbTo0NDM.&amp;hl=en&amp;v=v1526884278587&amp;size=normal&amp;cb=jssxsvw1wcmm" role="presentation" scrolling="no" sandbox="allow-forms allow-popups allow-same-origin allow-scripts allow-top-navigation allow-modals allow-popups-to-escape-sandbox" style="outline: 1px solid blue;" width="304" height="78" frameborder="0"></iframe>';
    var target  = str.split('k=')[1].split('&')[0];
    console.log(target);