不知道为什么我的验证器不起作用
[英]No idea why my validators aren't working
问题描述
Hi i am new to html and javascript. 
嗨，我是html和javascript的新手。 I encountered a problem which seems correct but it doesn't work. 我遇到了一个看似正确的问题，但是它不起作用。 There must be in problem in the function, which i can't figure it out. 函数中肯定有问题，我无法弄清楚。
<html> <body> <section> <form name="CombinationWithRep"> <h2>Combination with repetition</h2> N:<input type="text" name="numberOfThings" /> R: <input type="text" name="selection" /> <button onclick="CombinationWithRepfun()">Sub</button> <p id="demo1"></p> </form> <script langauge="javascript"> function CombinationWithRepfun() { var number = document.forms["CombinationWithRep"]["numberOfThings"].value; var selector = document.forms["CombinationWithRep"]["selection"].value; if (number == " ") { alert("pleas typo"); return false; } if (selector == " ") { alert("pleas typo"); return false; } var number1 = number * 1; var selector1 = selector * 1; document.getElementById("demo").innerHTML = Math.pow(number1, selector1); } </script> </section> </body> </html>
3 个解决方案
解决方案1
1 已采纳 2018-07-14 16:22:12
There are few issues in your code: 您的代码中有几个问题：
You are checking the value with a space (
您正在用空格检查值（ ), which I think you didn't wanted.），我认为您不想要。 You have to check the value with empty string. 您必须使用空字符串检查该值。 You can use
event.preventDefault()to prevent the event from further execution if the condition is true.如果条件为真，则可以使用event.preventDefault()阻止事件进一步执行。You should execute other code if the condition is false.
如果条件为假，则应执行其他代码。 You also have to use
demo1instead ofdemo.您还必须使用demo1而不是demo。 Try the following code:尝试以下代码：
<form name="CombinationWithRep"> <h2>Combination with repetition</h2> N:<input type="text" name="numberOfThings"/> R:<input type="text" name="selection"/> <button type="button" onclick="CombinationWithRepfun(event)">Sub</button> <p id="demo1"></p> </form> <script langauge="javascript"> function CombinationWithRepfun(e) { var number = document.forms["CombinationWithRep"]["numberOfThings"].value; var selector = document.forms["CombinationWithRep"]["selection"].value; if (number.trim() == "" || selector.trim() == "") { alert("pleas typo"); e.preventDefault(); } else { var number1 = number*1; var selector1 = selector*1; document.getElementById("demo1").innerHTML = Math.pow(number1, selector1); } } </script> </section>
解决方案2
0 2018-07-14 16:25:35
首先，在脚本标记中输入错误（“语言”而不是“ langauge”。）第二，我认为您需要使用parseInt或ParseFloat将数字1和选择器1从字符串转换为数字
解决方案3
0
Answers are below and here's how I would build that: https://codepen.io/yamato79/pen/YjwzQE hope this helps, have a nice day. 答案在下面，这是我的构建方法： https : //codepen.io/yamato79/pen/YjwzQE希望这对您有所帮助，祝您度过愉快的一天。
Add type="button"
<button type="button" onclick="CombinationWithRepfun()">Sub</button>attribute so it doesn't submit the form when you click on the button.添加type =“ button” <button type="button" onclick="CombinationWithRepfun()">Sub</button>属性，以便在单击按钮时不提交表单。 It keeps refreshing the page everytime you click the button because it's submitting the form to the same page.每次您单击按钮时，它都会刷新页面，因为它将表单提交到同一页面。 if (selector == "")if (number == "")Compare it with just quotes.if (selector == "")if (number == "")将其与引号进行比较。 You used " " which is not equal to the input being empty.您使用的“”不等于输入为空。 Change
<script langauge="javascript">to<script type="text/javascript">将<script langauge="javascript">更改为<script type="text/javascript">document.getElementById("demo1").innerHTML = Math.pow(number1, selector1);And lastly, your element ID was incorrect.最后，您的元素ID不正确。
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