How to pass the id of an element that triggers an `onclick` event to the event handling function

Instead of passing the ID, you can just pass the element itself:

<link onclick="doWithThisElement(this)" />

Or, if you insist on passing the ID:

<link id="foo" onclick="doWithThisElement(this.id)" />

Here’s the JSFiddle Demo: http://jsfiddle.net/dRkuv/