JS 正则验证的一些东西

1、验证固定电话(有分机号)

String.prototype.trim =  function() {return this.replace(/^\s+|\s+$/g,"");}function checkTel() {    var  area_code = document.getElementById("area_code").value.trim();    var  main_code = document.getElementById("main_code").value.trim();    var  ext_code = document.getElementById("ext_code").value.trim();    var telephone = "";    if(/^\d{7,8}$/.test(main_code)) {        if(!(/^\d{3,4}$/.test(area_code))) {alert("您的区号填写有误,区号应该是3~4位的数字!");return;}telephone = area_code+ "-" + main_code ;if(ext_code!= "") {telephone += "-" + ext_code;}}document.getElementById("telephone").value = telephone;}

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