how to add event listener to iframe

1var iframe = document.getElementById('myIFrame');
2iframe.contentWindow.body.addEventListener('mouseup', Handler);
3
4function Handler() {
5    alert('works');
6}

1var iframe = document.getElementsByTagName('iframe')[0],
2    iDoc = iframe.contentWindow     // sometimes glamorous naming of variable
3        || iframe.contentDocument;  // makes your code working :)
4if (iDoc.document) {
5    iDoc = iDoc.document;
6    iDoc.body.addEventListener('afterLayout', function(){
7                        console.log('works');
8                });
9};