It is possible, though I would not recommend it.
Messing with default browser behavior such as anchor tag clicks will generally frustrate a user and prevent them from returning to your page.
Furthermore, as dystroy stated in his answer, the legal strings attached to dropping iframes on your page usually explicitly forbids this kind of behavior.
That being said, returning false
from an event handler will prevent the browser from receiving the event:
document.getElementById('yourFrame').contentWindow.document.body.onclick = function () {
return false;
};
It is worth saying that this will not work if the iframe is in a different domain than where the script is running from. If that is the case, you will need to construct a transparent overlay div that swallows the click events and absolutely position it over the iframe.
Here is a fiddle demonstrating both approaches: http://jsfiddle.net/qX4fu/1/