function check_enter(e) { //e is event object passed from function invocation

	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) {
		keyword_search('keyword_search');
		return false;
	} else {
		return true;
	}

}