If you create a tag like this

<a href="#" id="test" onClick="alert('Test');">Test</a>

and then a jQuery method

$(document).ready(function(){
  $("#test").click();
  //or $("#test").trigger("click");
});

It will display the alert in FF, but not in IE.

The reason for this can be found in the "trigger" method of jQuery.

The line

fn = jQuery.isFunction( elem[ type ] || null )

returns true in IE, but false in FF if the type==="click" because in IE there is a default click() method in every DOM element.

1) In FF

the trigger method of jQuery does not find a "click" function defined in the DOM Element (fn===false) and therefor checks the "onclick" attribute, finds it and calls the function. --> CORRECT

// Handle triggering native .onfoo handlers
if ( !fn && elem["on"+type] && elem["on"+type].apply( elem, data ) === false )
val = false;

2) In IE

the trigger method of jQuery DOES find a "click" function (which exists in all IE DOM Elements!). This means fn===true. JQuery now ignores the "onclick" attribute and falls back to this.

// Trigger the native events (except for clicks on links)
if ( fn && donative !== false && val !== false && !(jQuery.nodeName(elem, 'a') && type == "click") ) {

Since our tag is "A" and the type is "click" no action will be performed!

A workaround

for this problem currently is:

$("#test").trigger("onclick");