Form validation in javascript

To check whether a radio button is checked or not:


function is_radio_checked(theForm,fieldname){
    var n=0;
    var rads =theForm.elements[fieldname];
    var valuee="";
    for(var i=0;i<rads.length;i++){
      if(rads[i].checked==true){
         valuee=rads[i].value;
         n=n+1;
      }
    }
    if(n==0){
      return false;
    }else{
      return selectedSingleValue;
    }
}

Input: Form name and name of radio field
Output: It will return the selected radio value and false if no radio is selected
Usage Example:

function checkform(theForm){
    if(is_radio_checked(theForm,'invoice_payment_statusID')==false){
        alert("Please select at least one option from status.");
        return false;
    }
}

=========== Importing value from pop up window to parent window===
function importAddress()
{


    var flag=0;
    val=new Array();
    var c=0;
    for (var i=0; i < document.form1.elements.length; i++)
    {

        if(document.form1.elements[i].name=='referID[]' && document.form1.elements[i].checked==true){
            flag=1;

            val[c]=document.form1.elements[i].value;
            c++;

        }

    }

    if(flag==0){
        window.close();
    }else{
        var selvalue =  val.join(",");
        window.opener.document.getElementById('recepient').value = selvalue;
        window.close();
    }

}