JavaScript 正则表达式 验证数字（包含小数），然后转成千分位的格式

function fmt(obj) {if(!isNum(obj.value)&&obj.value!=""){obj.value = "";showMsgPanel("<font style='color:red;'>請輸入數字！</font>", "系统提示");}else{var vb = obj.value;obj.value = fmtValue(vb);}}function unfmt(obj) {obj.value = obj.value.replace(/\,/g, "");obj.select();return obj.value;}function isNum(num){if(/^\d+(\.\d+)?$/.test(num)){return true;}return false;}function fmtValue(value) {var vb = value.split('.');var val = vb[0].replace(/\D/g, '');if (vb.length > 0) {var len = val.length;var fir = len % 3;var sb = [];if (len > 3) {if (fir > 0) {sb[sb.length] = val.substring(0, fir) + ",";}for (var i = fir + 3; i <= len; i += 3) {sb[sb.length] = val.substring(i - 3, i) + ",";}var end = sb[sb.length - 1];sb[sb.length - 1] = end.substring(0, end.length - 1);} else {sb[sb.length] = val;}return sb.join("")+ (vb.length > 1 ? (vb[1].length > 0 ? '.' + vb[1].substring(0,3) : ''): (vb[0].length > 0 ? '.000' : ''));}return "";}

一个输入框

<input name="custAccBal" type="text" class="textBox" style="height: 20px; 

width: 125px; border: solid 1px #6699cc; color: blue; font-weight: bolder;text-align:right" 

pattern="money"  autocheck="true" onblur="fmt(this);" onfocus="unfmt(this);">