jQuery textarea tab insert

jquery.tabinsert.js

  /*
   * Textarea tab insert
   * @dependence jQuery>=1.4.2
   * @dependence https://github.com/jeresig/jquery.hotkeys
   * @author Alexander Burtsev
   */
$('textarea', _form).bind("keydown", "tab", function(e) {
	if ( document.selection ) { // IE
		var iesel = document.selection.createRange().duplicate();
		iesel.text = "\t";
	} else {
		var	start = this.selectionStart,
			left = this.value.substring(0, start),
			right = this.value.substring(this.selectionEnd),
			scroll = this.scrollTop;

		this.value = left + "\t" + right;
		this.selectionStart = this.selectionEnd = start + 1;
		this.scrollTop = scroll;
		this.focus();
	}
	return false;
});