表單判斷（正則）

<div class="checkbox">
          <label>
              <input name="sex" class="sex" type="radio" value='1'>
              <span class='cr'>男</span>
          </label>
          <label>
              <input name="sex" class="sex" type="radio" value='2'>
              <span class="cr">女</span>
          </label>
        </div>
        <input name='name' class='name' type="text" class="text" value="姓名" onFocus="this.value = '';" onBlur="if (this.value == '') {this.value = '姓名';}">
        <input name='phone' class='phone' type="text" value="手機" onFocus="this.value = '';" onBlur="if (this.value == '') {this.value = '手機';}">
        <input name='mail' class='mail' type="text" class="text" value="郵箱" onFocus="this.value = '';" onBlur="if (this.value == '') {this.value = '郵箱';}" >
        <input name='address' class='address' type="text" value="詳細地址" onFocus="this.value = '';" onBlur="if (this.value == '') {this.value = '詳細地址';}">


var sex = $('input[name="sex"]:checked').val();
    var name = $('.name').val();
    var phone = $('.phone').val();
    var pl = phone.length;
    var mail = $('.mail').val();
    var address = $('.address').val();
    //正則判斷郵箱是精確的！
    var reg = /^\w+((-\w+)|(\.\w+))*\@[A-Za-z0-9]+((\.|-)[A-Za-z0-9]+)*\.[A-Za-z0-9]+$/;
    isok= reg.test(mail);

    //同理正則判斷手機號的格式是精確的! 驗證130-139,150-159,180-189號碼段的手機號碼
    var myreg = /^(((13[0-9]{1})|(15[0-9]{1})|(18[0-9]{1}))+\d{8})$/; 

    if(sex==null){
      alert('請選擇您的性別！');
      return false;
    }else if(name=='姓名'){
      alert('姓名不能爲空!');
      $('.name').focus();
      return false;
    }else if(phone=='手機'){
      alert('手機不能爲空!');
      $('.phone').focus();
      return false;
    }else if(pl!=11){
       alert('手機位數不正確！');
       $('.phone').focus();
       return false;
    }else if(!myreg.test(phone)) 
    { 
        alert('請輸入有效的手機號碼！'); 
        $('.phone').focus();
        return false; 
    } else if(mail=='郵箱'){
      alert('郵箱不能爲空!');
      $('.mail').focus();
      return false;
    }else if(!isok){
      alert("郵箱格式不正確，請重新輸入！");
      $('.mail').focus();
      return false;
    }else if(address=='詳細地址'){
      alert('詳細地址不能爲空!');
      $('.address').focus();
      return false;
    }