clearing a txt box

[Bluemonkey]

how can i clear a text field in my form when a user clicks on it.
ie it has a defult value attached to it but i want that to go wen u click on it.

thanks

[arnyinc]

<input type="text" name="user_input" onclick="this.value=''" value="Enter your text here">

[Bluemonkey]

thank you very much for the help