JS and jquery Verify the _javascript of the Radio box, check box and dropdown box respectively.

This paper describes the JS and jquery verification of the single box (radio), Multiple marquee (checkbox), Drop-down box (select), share for everyone to refer to, the specific content as follows
(1). First of all, the Radio box (radio),Radio and checkbox are the same name the same value has multiple when we get the radio value we can't follow the normal text box. Value, but to determine which is selected.

JS verification is to use Getelementsbyname () to get the array
The JS code is as follows:

 <script>
 function Test () {
 var sex = document.getelementsbyname ("Sex");
 var flag = 0;
 for (Var i=0;i<sex.length;i++)
 {
 if (Sex.item (i). checked = = true)
 {
  flag = 1;
  break;
 }
 }
 if (!flag)
 {
 alert ("Please select Gender");
 }
 </script>
 <input type= "Radio" name= "Sex" value= "M" > Male <input type= "Radio" name= "Sex" value= "F" > Female
 <input type= "button" id= "BTN" value= "submit" onclick= "Test ()" >

With jquery verification is much simpler, do less write more do, hehe:

<script src= "Jquery-1.7.1.min.js" ></script>
 <script>
$ (document). Ready (function () {
$ ("#btn"). Click (function () {
if ($ (": radio:checked"). Length = = 0)
{
alert ("Your sex is not selected")
;
} );
 </script>
 <input type= "Radio" name= "Sex" value= "M" > Male <input type= "Radio" name= "Sex" value= "F" > Female
 <input type= "button" id= "BTN" value= "Submit" >

(2) check box (checkbox), This is really needless to say, because the check box and the practice of the radio box is exactly the same, as long as the above script radio changed to checkbox on the OK!

(3) Drop-down box (SELECT)
Use JS verification, JS code:

<script>
function Test () {
var sex = document.getElementById ("Sex"). Value;
if (!sex)
{
alert ("Your sex is not selected");
}
 </script>
 <select id= "Sex" >
<option value= "" >--Please select gender--</option>
<option Value= "M" > Men </option>
<option value= "F" > Women </option>
 </select>
 <input Type= "button" id= "BTN" value= "submit" onclick= "Test ()" >

Using jquery authentication:

 <script src= "Jquery-1.7.1.min.js" ></script>
 <script>
$ (document). Ready (function () {
$ ("#btn"). Click (function () {
if ($ ("#sex"). val () = = ')
{
alert ("Your sex is not selected");
}});
 </script>
 <select id= "Sex" >
<option value= "" >--Please select Gender--</option>
<option value= "M" > Men </option>
<option value= "F" > Women </option>
 </select>
 <input type= "button" id= "BTN" value= "Submit" >

If you want to learn more, you can click the jquery dropdown box effect summary, JavaScript drop-down Box effect summary to learn.

The above is about JS and jquery verification of the single selection box, check box, drop-down box code, according to difficult to introduce, I hope to help you learn.