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javascript:void(0) meaning

高洛峰
高洛峰Original
2016-12-13 13:29:291581browse

We often use code like javascript:void(0), so what does javascript:void(0) mean in JavaScript? The most critical thing in

javascript:void(0) is the void keyword. void is a very important keyword in JavaScript. This operator specifies to calculate an expression but does not return a value.

The syntax format is as follows: 

<head>
<script type="text/javascript">
<!--
void func()
javascript:void func()

或者

void(func())
javascript:void(func())
//-->
</script>
</head>

The following code creates a hyperlink, and nothing will happen when the user clicks it. 

<a href="javascript:void(0)">单击此处什么也不会发生</a>

void(0) evaluates to 0 when user links, but has no effect on Javascript.

In the following example, a warning message is displayed after the user clicks the link: 

<head>
<script type="text/javascript">
<!--
//-->
</script>
</head>
<body>
<a href="javascript:void(alert(&#39;Warning!!!&#39;))">点我!</a>
</body>

In the following example, parameter a will return undefined: 

<head>
<script type="text/javascript">
<!--
function getValue(){
  var a,b,c;
  a = void ( b = 5, c = 7 );
  document.write(&#39;a = &#39; + a + &#39; b = &#39; + b +&#39; c = &#39; + c );
}
//-->
</script>
</head>

The difference between href="#" and href="javascript:void(0)"

# Contains a location information. The default anchor is #top, which is the top of the web page.

And javascript:void(0), just means a dead link.

When the page is very long, # will be used to locate the specific location of the page. The format is: # + id.

If you want to define a dead link please use javascript:void(0). 

<a href="javascript:void(0);">点我没有反应的!</a> 
<a href="#pos">点我定位到指定位置!</a> 
<br> 
... 
<br> 
<p id="pos">尾部定位点</p>


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