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>
<!DOCTYPE html>
<html>
<head>
<meta charset="utf-8">
<title>php中文网(php.cn)</title>
</head>
<body>
<a href="javascript:void(0)">点击此处什么也不会发生</a>
</body>
</html>
When the user links, void(0) evaluates to 0, but Nothing works on Javascript.
In the following example, a warning message is displayed after the user clicks the link:
<!DOCTYPE html>
<html>
<head>
<meta charset="utf-8">
<title>php中文网(php.cn)</title>
<script type="text/javascript">
</script>
</head>
<body>
<a href="javascript:void(alert('有误'))">点击</a>
</body>
</html>In the following example, parameter a will return undefined:
<!DOCTYPE html>
<html>
<head>
<meta charset="utf-8">
<title>php中文网(php.cn)</title>
<script type="text/javascript">
function getValue(){
var a,b,c;
a = void ( b = 5, c = 7 );
document.write('a = ' + a + ' b = ' + b +' c = ' + c );
}
</script>
</head>
<body>
<form>
<input type="button" value="单击" onclick="getValue();" />
</form>
</body>
</html>
The difference between href="#" and href="javascript:void(0)"
# contains a location information, the default anchor is #top, which is the web page the upper end.
And javascript:void(0) only represents 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);">点击没反应</a>
<a href="#pos">单击跳转</a>
<br>
...
<br>
<p id="pos">尾部定位点</p>
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