createTextRange() is a proprietary Internet Explorer scripting method which allows a script to examine and modify the text contained in an object or series of objects on the page. For instance, it could be used to change the text in a button or INPUT prompt.
Script Action Handlers are a programming construct in HTML scripting used by a programmer to define script to run in response to a specific event. For instance, an onmouseover() script action handler for a link will execute when the user moves the mouse over the link. Modern DHTML programming supports a large variety of script action handlers for response to user and program behavior.