javascript Accept terms

javascript Accept terms
before submitting the form you must accept term and condition
<script>
var checkobj
function agreesubmit(el){
checkobj=el
if (document.all||document.getElementById){
for (i=0;i<checkobj.form.length;i++){
var tempobj=checkobj.form.elements[i]
if(tempobj.type.toLowerCase()=="submit")
tempobj.disabled=!checkobj.checked
}
}
}

function defaultagree(el){
if (!document.all&&!document.getElementById){
if (window.checkobj&&checkobj.checked)
return true
else{
alert("Please read/accept terms to submit form")
return false
}
}
}
document.forms.agreeform.agreecheck.checked=false
</script>
<form name="agreeform" onSubmit="return defaultagree(this)">
<input name="agreecheck" type="checkbox" onClick="agreesubmit(this)"><b>I agree to the above terms</b><br>
<input type="Submit" value="Submit!" disabled>
</form>

Demo

http://dl.dropbox.com/u/3293191/r-ednalan/accept_term.html