Question

$(function () {
            var mainimagepanel = $("#blah1");
            var postimagepanel = $("#blah2");
   });

both object exist on the page where i run my $. can someone show me why i got exception mainimagepanel is not defined

the exception caused in Firebug or Chrome dev tool. so someone can tell me reason and how i can check that a input control exist on both.

Answer 1

Your variables are declared inside the anonymous function, and that is their scope. They do not exist outside that function. To fix it, you can do something like:

var mainimagepanel, postimagepanel;

$(function () {
  mainimagepanel = $("#blah1");
  postimagepanel = $("#blah2");
});

It is however usually good advice to limit your variables so that they exist in the tightest possible scope.