Question

What is the difference between the following statements?

<tr onclick="javascript:class1.function1()">
<td>HideAlert</td>
</tr>

and

<tr onclick="class1.function1()">
<td>HideAlert</td>
</tr>

I created a webpage with the second method for calling the function and tested in Internet Explorer 6.0 which came with Windows 2003 Server. The function is not called. When i gave “javascript:class1.function1()” in the browsers addressbar, then the function worked. Is there any difference in calling the function with the above mentioned ways?

The script is like below:

<script type="text/javascript">
var class1 = function(obj) {
this.val1 = obj.val1;
}
class1.function1 = function() {
$('#alertDiv').fadeOut('slow', function() {
});
</script>

The jquery version is 1.4.2

Answer 1

In the address bar (or in an href attribute, or anywhere else a regular URL might go), javascript: is the protocol that identifies a piece of JavaScript to be run in the current page.

In an onclick attribute (or any other script context), javascript: is a label which may be used like this:

javascript:
for( var i=0; i<100; i++) {
    while(true) {
        continue javascript;
    }
}
// bad example, but it works and doesn't cause an infinite loop!

In other words, onclick="javascript:..." is unnecessary.