obj has no properties

When I hit Submit on my form page I get this JavaScript error

[code=php]obj has no properties[/code]

The function my webdeveloper extension in Firefox points to is this:

[code=php]function checkRadio( obj )
{
for ( var i = 0; i < obj.length; i++ )
{
if ( obj[i].checked )
{
return true;
}
}
return false;
}[/code]

This function is called by:

[code=php]function validateRadio( obj )
{
var bChecked = checkRadio( obj );

for ( var i = 0; i < obj.length; i++ )
{
toggleError( obj[i], !bChecked );
}

return ( bChecked !== false );
}[/code]

Can someone help me out?

Also in #JavaScript _↴