function checkEnter(e) {
	var characterCode // literal character code will be stored in this variable

	if(e && e.which) { // if which property of event object is supported (NN4)
		e = e;
		characterCode = e.which; //character code is contained in NN4's which property
	} else{
		e = event;
		characterCode = e.keyCode;  //character code is contained in IE's keyCode property
	}

	if(characterCode == 13) { 
		document.forms[0].submit();
		return false;
	} else{
		return true;
	}
}