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Select corresponding select option by value

Posted on 2006-10-19
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1,600 Views
Last Modified: 2008-02-01
Hi,

I have a select object and the following script
document.getElementsByName(objSel).length
is giving me 1

I have four options in it
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Question by:JoeUS
  • 3
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5 Comments
 
LVL 12

Expert Comment

by:netsmithcentral
ID: 17770328
document.getElementsByName(name) returns an array containing object references to every object with that name on a page.  To access the acutal object you have to refer to it's number within the array:

document.getElementsByName(objSel)[0].length; <== will return the length of the select.

A better method is to use the document.getElementById(id) method.  This returns exactly one object, the one with a given ID.
0
 

Author Comment

by:JoeUS
ID: 17770810
In this case I am looking for the lenght of the array
 
I set a (var selVal) in global and would like to automatically set "selectedIndex" for
the corresponding select option at form onLoad

smtng like:

<script>
function setSelEcho() {
var selVal = 'foo3';
var inputs = document.getElementsByName('objSel');
for(var i=0; i < inputs.length; i++) {      
        if(inputs.option[i].value == selVal ) {
                inputs.option[i].selectedIndex= true;
          }      
     }
}
</script>

<body onLoad="setSelEcho();">
<form>
<select id="objSel" name="objSel">
<option value="foo2">foo2</option >
<option value="foo3">foo3</option >
<option value="foo4">foo4</option >
</select>
</form>
</dody>
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LVL 12

Accepted Solution

by:
netsmithcentral earned 500 total points
ID: 17771016
<script>
function setSelEcho() {
var selVal = 'foo3';
var inputs = document.getElementsByName('objSel');
for(var i=0; i < inputs.length; i++) {      
        if(inputs[0].option[i].value == selVal ) {
                inputs[0].option[i].selectedIndex= true;
          }      
     }
}
</script>

<body onLoad="setSelEcho();">
<form>
<select id="objSel" name="objSel">
<option value="foo2">foo2</option >
<option value="foo3">foo3</option >
<option value="foo4">foo4</option >
</select>
</form>
</dody>
0
 

Author Comment

by:JoeUS
ID: 17773949
my inputs.length still returning 1
any idea why?
0
 

Author Comment

by:JoeUS
ID: 17775891
//I did work with this one quite hard and don't want anyone to spend the time on this more than
it is absolutely necessary

Thank you netsmithcentral for the hint, it finally lead me to the solution

<html>
<script language="JavaScript" type="text/javascript">
function setSelEcho() {
var selVal = 'foo3';
var inputs = document.getElementsByName('objSel');

//Important!!! to go after the "inputs[0]" or else will not find the object and see the options
//I am not sure if it has anything to do with multiple forms on the same page
var nops = inputs[0].options.length;

for(var i=0; i < nops; i++) {
        if(inputs[0].options[i].value == selVal ) {
                inputs[0].options[i].selected=true;
          }      
     }
}
</script>

<body onLoad="setSelEcho();">
<form>
<select id="objSel" name="objSel">
<option value="foo2">foo2</option >
<option value="foo3">foo3</option >
<option value="foo4">foo4</option >
</select>
</form>


</dody>
</html>
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