function CheckAgree() {
 var mysubmit = document.getElementById("submitid");
 var mycheckbox = document.getElementById("checkboxid");
 if (mycheckbox.checked==false && document.getElementById("username_error").innerHTML==" OK "){
	 mysubmit.disabled=true;
 }else{
	 mysubmit.disabled=false;
 }
}
	