用于检查网页中文本框是否为空的Java脚本. [英] java script to check if the textboxes in the webpage are empty or not..

问题描述

你好朋友，

我想知道如何编写Java脚本来检查文本框，下拉列表是否为空.如果它们为空，则应调用css类并在该文本框中显示一条消息. br/>

 如果(文档 .getElementById( txtName').value == ')
{} 

下拉列表选择是否为空:

 <  选择 > ; 
<  选项     值  = "  >  123 ><  /option  > 
<  选项    ="   234" <  > 
<  /select  >  

  var  hasValue =(
 
 
(' 选择> [selected]').length>  0 ); 

Hello Friends,

I want to know how to write a java script to check if the text-boxes, dropdown list are empty or not. And if they are empty it should call a css class and display a message within that text box.

解决方案

Sample JavaScript to validate the text box is empty or not:

if (document.getElementById('txtName').value=='')
{}

dropdown list select is empty or not:

<select>
<option selected value="123">123</option>
<option value="234">234</option>
</select>

var hasValue = (

('select > [selected]').length > 0);

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