function insert_tab ( event, obj ) {
	var tKeyPressed;
	if ( event.which )
		tKeyPressed=event.which; 	// gecko
	else
		tKeyPressed=event.keyCode;	// IE
	if ( tKeyPressed == 9 ) {
		if ( event.type == "keydown" ) {
			if ( obj.setSelectionRange ) {
				var s=obj.selectionStart;
				var e=obj.selectionEnd;
				obj.value = obj.value.substring(0, s) + "\t" + obj.value.substr(e);
				obj.setSelectionRange(s+1,s+1);
				obj.focus();
			} else if (obj.createTextRange) {
				document.selection.createRange().text="\t";
				obj.onblur = function() { this.focus(); this.onblur = null; };
			}
		}
		if ( event.returnValue )
			event.returnValue=false;
		if ( event.preventDefault )
			event.preventDefault ();
		return false;
	}
	return true;
}