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Validation for multiple select list box

14 New Member
I am using a multiple select list box.

I use an array to retrieve the values that are selected by the user.

Expand|Select|Wrap|Line Numbers
  1. <select name="competitor[]">
When I try to validate the list box if the user does not select anything, I get errors. The error deals with the array declared.

I am using PHP and the validation is done in Javascript. Please help out.

Thanks in advance.
Apr 14 '09 #1
3 12266
608 Contributor
Expand|Select|Wrap|Line Numbers
  1. <html>
  2. <head>
  3. <script type="text/javascript">
  4. function selectMultiple()
  5.   {
  6.     var myArray="";
  7.          try
  8.           {
  9.            for (var i=0; i<document.getElementById('mySelect').options.length; i++)
  10.           { 
  11.                       if (document.getElementById('mySelect').options[i].selected == true) 
  12.                        { 
  13.                           //alert(document.getElementById('mySelect').options[i].text);
  14.               myArray += document.getElementById('mySelect').options[i].text + ";";
  15.                         } 
  16.           }
  18.            var resArray = myArray.split(";");
  19.            if(resArray.length<=1) 
  20.              alert("Please select the values in the list");
  21.            else 
  22.              alert("You have selected = "+(resArray.length-1));             
  23.          }
  24.         catch(e)
  25.         {
  26.            alert(e.message);    
  27.         }
  29. }
  30. </script>
  31. </head>
  32. <body><form>
  33. <select name="mySelect" size="10" multiple>
  34.   <option>Apple</option>
  35.   <option>Pear</option>
  36.   <option>Pea</option>
  37.   <option>Banana</option>
  38.   <option>Orange</option>
  39.   <option>Mango</option>
  40.   <option>Lime</option>
  41.   <option>Goa</option>
  42.   <option>Dates</option>
  43. </select>
  44. <input type="button" onclick="selectMultiple()" value="Select multiple">
  45. </form></body>
  46. </html> 
This is a validation for the multiple select box. As you were specifying array. I did this way. But i am not clear wether r u looking for this kind of validation or not.

Ramanan Kalirajan
Apr 14 '09 #2
16,027 Recognized Expert Moderator MVP
I don't think that's what he meant and anyway, the code is incorrect because the select element has no ID.

You can get the element by name:
Expand|Select|Wrap|Line Numbers
  1. document.forms[formname].elements["competitor[]"];
then get its options and validate.
Apr 14 '09 #3
2,476 Top Contributor
is "name[]" that a valid name?
Apr 15 '09 #4

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