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How do i test if a radio button collection exists?

Posted on 2004-04-27
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Last Modified: 2012-06-27
Hello, I have the below code:

            for(i=0; i<document.form1.PackageID.length; i++) {
                  if(document.form1.PackageID[i].checked==true) {
                        if((document.form1.PackageID[i].value)!='') {
                              PackageSelected = 1;
                        }
                  }
            }

I have XML dynamically generating a run of <input type=radio>'s on the fly with the NAME="PackageID", But if this FOR loop attempts to test before the radio's exist I get an error:
document.form1.PackageID.length is null or not an object

Can i test like an isExist or isNull in javascript? If so, is that what i use?
Thanks in advance...
0
Comment
Question by:Darren_Fryer
  • 3
5 Comments
 
LVL 35

Expert Comment

by:[ fanpages ]
ID: 10936113
Hi Darren_Fryer,

This link may help :)
http://www.crockford.com/javascript/remedial.html

BFN,

fp.
0
 
LVL 35

Accepted Solution

by:
[ fanpages ] earned 250 total points
ID: 10936117
...specifically:

function isNull(a) {
    return typeof a == 'object' && !a;
}

function isObject(a) {
    return (a && typeof a == 'object') || isFunction(a);
}

function isFunction(a) {
    return typeof a == 'function';
}


BFN,

fp.
0
 

Author Comment

by:Darren_Fryer
ID: 10936197
Thank you very much!
isObject worked brilliantly.
0
 
LVL 63

Expert Comment

by:Zvonko
ID: 10936222



  rBttn = document.form1.PackageID;
  if(rBttn){
     if(rBttn.length){
         for(i=0; i<rBttn.length; i++) {
              if(rBttn[i].checked==true) {
                   if((rBttn[i].value)!='') {
                        PackageSelected = 1;
                   }
              }
         }
    }else{
       if(rBttn.checked && rBttn.value!=""){
         PackageSelected = 1;
       }
    }
  }



0
 
LVL 35

Expert Comment

by:[ fanpages ]
ID: 10936284
Hi again,

Thanks for the points/grading.

Happy codin',

BFN,

fp.
0

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