html代碼：
<div class="reg_con" style="position:relative;">
<label>聯繫電話</label>
<input id="telphone" type="text" name="userExt.telphone" value="13800000000" class="inp" maxlength="11" />
<div id="telphone_tip" style="position:absolute; right:-90px;top:20px; color:#c00; font-weight:bold;">
</div>
</div>
JS代碼：
$("#telphone").blur("blur",function(){
var telphone = $("#telphone").val();
var myreg = /^1[34578]\d{9}$/;
if(telphone == ""){
$("#telphone_tip").html("聯繫電話不能爲空");
}
else
{
if(myreg.test(telphone)){
$("#telphone_tip").html("");
}
else
{
$("#telphone_tip").html("聯繫電話格式不正確");
};
};
});