How to periodically take value from form using javascript

[Gaijin]

I have the following html form:\[code\]<form name="form1"> <fieldset> <legend>Enter Color Name:</legend> <input type="text" name="textbox"/> </fieldset> </form>\[/code\]I want to extract the color name from the text box periodically (without using a submit button), using javascript. Thanks in advance!