Browsers Targeted: Internet Explorer 4 and 5

With Internet Explorer 4.0 and above, you can create an arbitrary property on any HTML object. This property, called an expando property, stays associated with the object as long as the object exists. For example, if you wanted to keep track of the number of times a given element has been clicked, you could create an expando property called clickCount that would retain the information for that element:

 
Click on a line to change its count:
This line has been clicked 0 times.
This line has been clicked 0 times.
This line has been clicked 0 times.

You can retrieve and set the values of an expando property with the .getAttribute and .setAttribute methods. SetAttribute will also add an expando property if one doesn’t exist, so you should use this method carefully?it is possible to misspell a property (including using the wrong case) and end up with a property you didn’t intend. You can turn the ability to use expando properties on or off with the document.expando property. When expando is true, you can create new expando properties; with it off, you can’t, nor can you access the values of any expando properties you’ve previously created. Note that expando only applies to HTML objects?VBScript objects don’t support it in any currently available implementation.