• Status: Solved
  • Priority: Medium
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Default Value of select

I have a validation to check whether the value in the form is changed. I have a problem when the component is a select. I have written a javascript but it is not working in some cases.
My funciton is:

function isChanged() {
 for(i=0;i<document.forms[0].elements.length;i++) {
    if(document.forms[0].elements[i].type=="select-one) {
        for(j=0;j<document.forms[0].elements[i].options.length;j++) {
            if(document.forms[0].elements[i].options[j].selected !=
                        document.forms[0].elements[i].options[j].defaultSelected) {
                return true;
          }
        }
    }
 }
}

In my case i dont have a default value selected in the combo box. I am using the html:select.
0
kanuaravind
Asked:
kanuaravind
1 Solution
 
gam3r_3xtr3m3Commented:
maybe...:

function isChanged() {
 for(i=0;i<document.forms[0].elements.length;i++) {
    if(document.forms[0].elements[i].type=="select") {
        for(j=0;j<document.forms[0].elements[i].options.length;j++) {
            if(document.forms[0].elements[i].options[j].selected !=
                      document.forms[0].elements[i].options[j].defaultSelected) {
                return true;
         }
        }
    }
 }
}

gam3r
0
 
lil_puffballCommented:
If you use defaultSelected, you must have

<option selected>

If you don't, it won't work.
You can assume that the default selected is 0, though, since if you don't specify it, the browser will automatically make it option 0. So you can use this code:

function isChanged() {
var selIndex=0;
 for(i=0;i<document.forms[0].elements.length;i++) {
    if(document.forms[0].elements[i].type=="select-one") {
        for(j=0;j<document.forms[0].elements[i].options.length;j++) {
            if(document.forms[0].elements[i].options[j].defaultSelected){selIndex=j;}
        }
        if(document.forms[0].elements[i].options.selectedIndex!=selIndex){return true;}
    }
 }
return false;
}
0
 
VincentPugliaCommented:
Hi,

  If you are using a select, the default value is usually option[0].  So, you should only need to check the selectedIndex:

function isChanged()
{
   for(i=0;i<document.forms[0].elements.length;i++)
  {
      if(document.forms[0].elements[i].type=="select-one)
     {
         var selObj = document.forms[0].elements[i];
         if (! selObj.options[0].selected)
             return true;
      }
  }
}

Vinny
0
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brgivensCommented:
Vinny's right, you only need to check the selectedIndex.  His code won't work though - try this:

function isChanged() {
 var i,o;
 for(i=0;i<document.forms[0].elements.length;i++) if((o=document.forms[0].elements[i]).type=="select-one" && !o.options[o.selectedIndex].defaultSelected) return true;
 return false;
}
0
 
VincentPugliaCommented:
Hi brgivens,

  I admit I didn't test what I had written until your last post.  It works for me (as long as the quote is closed -- 'select-one')

<script type='text/javascript'>
function isChanged()
{
   for(i=0;i<document.forms[0].elements.length;i++)
   {
      if(document.forms[0].elements[i].type=="select-one")
     {

alert(selObj.options[0].selected)

         var selObj = document.forms[0].elements[i];
         if (! selObj.options[0].selected)
             return (true);
      }
  }
}
//-->
</script>
</head>
<body>
<form onsubmit='isChanged()'>
<select>
<option >select</option>
<option >select</option>
<option >select</option>
</select>
<input type="submit">
</form>

The presumption I am making is that the first option is the default.

Vinny
0
 
brgivensCommented:
Thanks for the points!  Why the B?
0

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