function validate_callback(){
var detailsOK=true;

 if (document.callback.callback_tel.value.length <8) {
  detailsOK=false;
 }
 
 if (IsNumeric(document.callback.callback_tel.value) == false) {
  alert("Please enter a valid telephone number including the area code ensuring there are no spaces");
  detailsOK=false;
 }
 
 
// Submit?
 if(detailsOK==false){
 }else{
		// Transfer Tel Num into popup form
		document.callbackv2.callback_tel.value=document.callback.callback_tel.value;
  		//centering with css
		centerPopup();
		//load popup
		loadPopup();
 } 
 
}