Create new instance of the class.
var ai = new mrasnika_active_input();
Set the background colors you want to use.
ai.setNormalBackground('#eeeeee');
ai.setActiveBackground('#aaeeaa');
Attach the Run() method to the onLoad event.
<body onLoad="ai.Run();">
Here's the whole thing
<html>
<head>
...
<!-- include JS file -->
<script src="active-input.js"></script>
<script>
<!--//
/**
* Create new object
*/
ai = new mrasnika_active_input();
/**
* Set the colors
*/
ai.setNormalBackground('#eeeeee');
ai.setActiveBackground('#aaeeaa');
//-->
</script>
...
</head>
<body onLoad="ai.Run();">
...
</body>
<html/>
This is a test page to demonstrate the JavaScript class which applies different color (highlights) to the input, that currently has the focus