Code
<HEAD>
<SCRIPT LANGUAGE="JavaScript">
<! >
<! >
<!-- Begin
agree = 0; // 0 means 'no', 1 means 'yes'
// End -->
</script>
</HEAD>
<!-- STEP TWO: Copy this code into the BODY of your HTML document -->
<BODY>
<center>
<form name=enableform>
You can only enter your name if you agree to the terms. (just a demo)<br>
<br>
<input type=radio name='enable' value='agree' onClick="agree=1; document.enableform.box.focus();">I agree<br>
<input type=radio name='enable' value='disagree' onClick="agree=0; document.enableform.box.value='';">I disagree<br>
Please enter your name:
<input type=text name=box onFocus="if (!agree)this.blur();" onChange="if (!agree)this.value='';" size=12>
<br>
<br>
<input type=submit value="Done!">
</form>
</center>
