如何使用javascript验证下拉列表？ [英] how to validate a dropdownlist using javascript?

问题描述

我想如何在asp.net中使用javascript验证下拉列表？

How i want to validate a dropdownlist using javascript in asp.net???

推荐答案

使用以下JS脚本

Hi,

Use below JS script

function JSFunctionValidate()
{
if(document.getElementById('<%=ddlView.ClientID%>').selectedIndex == 0)
{
alert("Please select ddl");
return false;
}
return true;
}

如果你想查看价值然后写一下

if you want to check with value then write

objDDl = document.getElementById('<%=ddlView.ClientID%>');
if(objDDl.options[objDDl.selectedIndex].value == "")
{
alert("Please select ddl");
return false;
}

这有点容易。看下面这个函数

it's bit easy. see the following function

function validate()
{
   if(document.getElementById("ddlList").value == "")
   {
      alert("Please select value"); // prompt user
      document.getElementById("ddlList").focus(); //set focus back to control
      return false;
   }
}

假设你的select元素看起来像这样

Assuming your select element looks like this

<select id="ddlView">
<option value="0">Select</option>
<option value="1">test1</option>
<option value="2">test2</option>
<option value="3">test3</option>
</select>

function Validate()
{
var e = document.getElementById("ddlView");
var strUser = e.options[e.selectedIndex].value;
//if you need text to be compared then use
var strUser1 = e.options[e.selectedIndex].text;
if(strUser==0) //for text use if(strUser1=="Select")
{
alert("Please select a user");
}
}

这篇关于如何使用javascript验证下拉列表？的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！