preventDefault()方法用于阻止浏览器执行所选元素的默认操作。它可以阻止用户通过单击链接来处理请求。
句法：
event.preventDefault()参数：它不接受任何参数。
事件用于表示用户响应该方法起作用的事件或动作。
代码#1：
此代码将阻止浏览器转到另一个页面。
GEEKSFORGEEKS ARTICLE<title/>
<!-- INCLUDE THE JQUERY CDN -->
<script src="https://ajax.googleapis.com/ajax/
libs/jquery/3.3.1/jquery.min.js"></script>
<script type="text/javascript">
$(document).ready(function()
{
$("a").click(function(event)
{
event.preventDefault();
alert("prevented");
});
});
</script>
</head>
<body>
<p>Click the link:</p>
<a href="https://www.google.com">GOOGLE</a>
</body>
</html>
</code></pre>
</div>
<p><strong>输出：</strong><br/>它显示了如下所示的输出- <br/><img alt="" class="img-fluid" src="https://mangodoc.oss-cn-beijing.aliyuncs.com/geek8geeks/preventDefault()_Event_Method_0.jpg"/><br/><strong>代码#2：</strong><br/>此代码将阻止浏览器将页面重定向到另一个PHP文件。 </p>
<div class="hcb_wrap">
<pre class="prism line-numbers lang-js" data-lang="JavaScript"><code class="replace"><html>
<head>
<title>GEEKSFORGEEKS ARTICLE<title/>
<script src="https://ajax.googleapis.com/ajax/
libs/jquery/3.3.1/jquery.min.js"></script>
<script type="text/javascript">
$(document).ready(function()
{
$("#submit").click(function(event)
{
event.preventDefault();
alert("ACTION IS PREVENTED");
});
});
</script>
</head>
<body>
<form action="submit.php">
<input type="text" placeholder="enter username">
<input id="submit" type="submit" name="submit">
</form>
</body>
</html>
</code></pre>
</div>
<p><strong>输出：</strong><br/>它显示了如下所示的输出- <br/><img alt="" class="img-fluid" src="https://mangodoc.oss-cn-beijing.aliyuncs.com/geek8geeks/preventDefault()_Event_Method_1.jpg"/></p>
<div class="_ap_apex_ad" id="82d2079a-8120-480f-9fc7-5cda825d56e7" style="min-height:280px"></div>
<p></p></div>
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