光标定位于文字后

function set(citeownername,uid)
{
	document.getElementById("contents").value =citeownername;
	document.getElementById("replytoUid").value =uid;
	var e =document.getElementById("contents");
	var content = e.value;
	var num=content.replace(/[^\u0000-\u00ff]/g, "aa").length;
	e.focus();
	var r =e.createTextRange();
	r.moveStart('character',num);
	r.collapse(true);
	r.select();
}