set/get dynamically custom attribute

Question

Major modern browsers support setting/retrieving custom attribute dynamically, except IE-family. How can I set/get my custom attribute in all browsers?

This is what I've tried so far:

HTML:

<input id="myInput" type="text" />

JS:

var myInput = document.getElementById('myInput');
myInput.setAttribute('custom-attr', 'custom-value');
alert(myInput.getAttribute('custom-attr'));

or

var myInput = document.getElementById('myInput');
var customAttr = document.createAttribute('custom-attr');
customAttr.value = 'custom-value';
myInput.setAttributeNode(customAttr);
alert(myInput.getAttribute('custom-attr'));

In both cases IE alert() returns null.

Answer 1

I tested your code on IE7/8

var myInput = document.getElementById('myInput');
myInput.setAttribute('custom-attr', 'custom-value');
alert(myInput.getAttribute('custom-attr'));

and it runs fine. Does that simple test case fail for you, or are you actually doing something different?

You can use bracket notation

var myInput = document.getElementById('myInput');
myInput['custom-attr'] = 'custom-value';
alert(myInput['custom-attr']);

If you did not have the - in the name, you can use dot notation

var myInput = document.getElementById('myInput');
myInput.customAttr = 'custom-value';
alert(myInput.customAttr);

Answer 2

Your code works just fine on IE6, IE7, IE8, FF, Chrome, Opera.