在js中进行表单验证
问题描述：
我正在验证表单，我不确定是否使它比需要更复杂。我有一个变量，我比较的元素，然后成功取代IMG SRC检查成功或X失败。它应该运行我的validateData函数，一旦该领域未聚焦。这是js。当我通过输入数字来触发redx.png src变化来测试第一个字段时，我的img src src不会改变。在js中进行表单验证
function validateData() {
var letters = /^[A-Za-z]+$/;
var image1=document.getElementsById("image1");
if (document.forms["quiz_form"]["last_name"].value.match(letters) && document.forms["quiz_form"]["last_name"].value!="")
{
image1.src="check.png";
}
else{
image1.src="redx.png";
}
}
<!DOCTYPE html>
<html>
<head>
<title></title>
<meta name="author" content="Kenneth Dunn" />
<meta name="description" content="" />
<script src="quiz.js"></script>
<link rel="stylesheet" href="quiz.css" type="text/css" />
</head>
<body>
<div id="page">
<div id="logo">
<h1><a href="https://playoverwatch.com">Overwatch</a></h1>
</div>
<div id="content">
<h2>Overwatch Quiz</h2>
<p>
Hi there!
This quiz is dedicated to one of my favorite games Overwatch!
</p>
<form action="quiz.js" method="post" name="quiz_form">
<p><br>
<input name "first_name" type="text" placeholder="First Name" onblur="this.placeholder='First Name'" onfocus="this.placeholder='Use only letters'" onblur="validateData()"/>
<img src='http://www.q-park.ie/Portals/8/images/search-icon.png' id="image1" class="image1"/>
</p>
<p><br>
<input name="last_name" type="text" placeholder="Last Name" onblur="this.placeholder='Last Name'" onfocus="this.placeholder='Use only Letters'" onblur="validateData()" />
<img src='http://www.q-park.ie/Portals/8/images/search-icon.png' id="image2" class="image2"/>
</p>
<p><br>
<input name="email" type="text" placeholder="Email" onblur="this.placeholder='Email'" onfocus="this.placeholder='Must contain @ '" onblur="validateData()"/>
<img src='http://www.q-park.ie/Portals/8/images/search-icon.png' id="image3" class="image3"/>
</p>
<p><br>
<input name="number" type="text" placeholder="Phone Number" onblur="this.placeholder='Phone Number'" onfocus="this.placeholder='Must follow xxx-xxx-xxx '" onblur="validateData()" />
<img src='http://www.q-park.ie/Portals/8/images/search-icon.png' id="image4" class="image4"/>
</p>
<p><br>
<input name="sulley" type="text" placeholder="Sulley Email" onblur="this.placeholder='Sulley Email Address'" onfocus="this.placeholder='Must contain ~ and https:// '" onblur="validateData()" />
<img src='http://www.q-park.ie/Portals/8/images/search-icon.png' id="image5" class="image5"/>
</p>
<br>
<br>
<p>
<h2>Find out which Overwatch character you are most like!</h2>
<p>If you could pick what form to take in a fictional universe with magic and cool science what would you want to be?</p>
<input type="radio" name="exist" value="1">Male(Human).<br>
<input type="radio" name="exist" value="2">Female(Human).<br>
<input type="radio" name="exist" value="3">An Animal or something crazy.
<p>What is your preferred weapon to take on bad guys and defend yourself?</p>
<input type="radio" name="weapon" value="1">Twin Shotguns for close range.<br>
<input type="radio" name="weapon" value="2">Twin pistols medium range.<br>
<input type="radio" name="weapon" value="3">An electro gun that schocks enemies into submission.
<p>Which motivations most align with your own?<p>
<input type="radio" name="idea" value="1">To become more powerful and to defeat those who would oppose me.<br>
<input type="radio" name="idea" value="2">To explore the world and discover the unknown.<br>
<input type="radio" name="idea" value="3">To protect my friends and those I care about.
<p>What do you look like?</p>
<input type="radio" name="look" value="1">Dark and mysterious black-hooded figure ,very edgy, like people in the Matix.<br>
<input type="radio" name="look" value="2">Short and spunky British airforce pilot who can travel back in time.<br>
<input type="radio" name="look" value="3">I'm a large gorilla who likes to eat bananas and peanut butter and can sheild my friends from harm.
<br>
<br>
<input type="submit" name="submit" id="submit" value="submit" />
<input type="reset" name="reset" id="reset" value="Reset" />
</p>
</form>
<br>
<br>
<br>
<br>
<div id="footer">
<h2 align="center" >Created by </h2>
</p>
</div>
</div>
</div>
</body>
</html>
答
你不能只是简单地设置action你的JS脚本，您将需要使用onsubmit事件处理程序。
<form onsubmit="validateData">
一旦提交表单这将触发validateData方法。这不会执行，虽然像往常一样停止形式，你需要停止在您的validateData方法，像这样：
function validateData (event) {
// prevent the form from actually submitting
event.preventDefault();
}
答
这里有多个问题;有些已被别人提及。其中一个主要问题是您有getElementsById而不是getElementById。如果您还没有弄清楚如何拉开开发者控制台并查看您遇到的错误，现在将是一个好时机。
表单验证可能会变得非常复杂，通常我会使用一个库来完成繁重的工作。你可以看看。
这是我猜你正在尝试做的工作版本。这远非最佳，但这正是我很快就能想出来的。
什么问题？你的HTML在哪里？ –
@CarlMarkham img src在测试时不会改变，我不知道为什么。我已经更新它来添加我的HTML。 – Phlash6
每个输入上都有两个onblur =“”。你不应该用JS处理占位符文本，使用placeholder =“Some Text”属性。 – xCNPx