Hello I'd like to know how to do this:

I have an HTML form for subscription to my e-mail mailing list, i have setup the e-mail to value="Your Email Address", i would like to make this value disapear when someone click in the e-mail field to position the cursor and write his e-mail?

Thanks in advance for the help

regards
M-Ex

<input type="text" name="textfieldName" value="blah blah" size="24" onfocus="this.value='';">