TextBox 千分位自動加上逗號

畫面上新增一個 AMT_txt (Textbox)
Page_Load加入 AMT_txt.Attributes("onkeyup") = "trans_amt('" + AMT_txt.ClientID + "');" 
以下為JavaScript 注意JavaScript的replace只取代第一個相同的字串 必須加上/\ /g

function trans_amt(Name) {
var amt = document.getElementById(Name).value;
var amt_length = amt;
amt = amt.replace(/\,/g, "");
re = /(\d{1,3})(?=(\d{3})+(?:$|\D))/g;
n1 = amt.replace(re, "$1,");
document.getElementById(Name).value = n1;
//var sel = document.selection.createRange();
//sel.moveStart('character', amt_length.length);
//sel.collapse(true);
//sel.select();
}