asked on

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.

gam3r_3xtr3m3

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

lil_puffball

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;
}

VincentPuglia

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

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brgivens

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VincentPuglia

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

brgivens

Thanks for the points! Why the B?