html - Check if link is clicked in JavaScript -

edit: question different 'supposedly duplicate' because mine checking how not trigger off event when link clicked, other question how detect changes in form.

i using function (taken here) detect changes made form before leaving page, works fine triggers off when click save button using onbeforeunload event fire of function , want prevent happening when click save button.

here event:

window.onbeforeunload = function (e) {     e = e || window.event;     if (formisdirty(document.forms[0])) {         // ie , firefox         if (e) {             e.returnvalue = "you have unsaved changes.";             alert("you have unsaved changes.");         }         // safari         return "you have unsaved changes.";         alert("you have unsaved changes.");     } }; 

how can prevent event firing when particular save link clicked?

link:

<a id="ctl00_contentplaceholder1_lbtnsave" href='/save'> <img id="ctl00_contentplaceholder1_image5" class="imgvalign" src="../../images/icons/save.gif"> save  </a> 

event.target //dom object.  event.target.id  //id of source element.  sourceelement = $(event.target.id); // jquery object 

you can check element submit button or not.if yes no need display message