Using Javascript's typeof on DOM elements to check undefined (IE problem) -

i want iterate on list of dom elements (check boxes) , keep going long list defined. elements 'c1r1', 'c1r2', 'c1r3', etc. once hit undefined one, stop. problem seems using typeof dom elements.

here's offending code:

function domisdefined(idstring){     alert(idstring);     var isitdefined = (typeof $(idstring) != 'undefined');     alert(isitdefined);     return isitdefined; } ... for(i=1; domisdefined('c1r' + i); i++){     if($('c1r' + i).checked==true){         // stuff     } } 

the crux of problem line:

var isitdefined = (typeof $(idstring) != 'undefined'); 

the problem, found out, typeof $(idstring) returns object, whether defined or not. there way sort of thing? guess i'll put in try catch , check .checked property early, feels disgusting.

function domisdefined(idstring){     return !!document.getelementbyid(idstring); }