trigger.('click') ill not triggering the native click event on IE8

trigger.('click') ill not triggering the native click event on IE8

i have done the following code on an hidden fiel on IE8 :
jQuery('#myfield').trigger('click')
But it's not working. On safari, i had the same problem, so i used :
var evt = document.createEvent("HTMLEvents");
evt.initEvent("click", true, true);
document.getElementById('myfield').dispatchEvent(evt);
But this code is not working too on IE8.
Do you know what i coul used on IE8?
Thanks in advance