Is this jQuery? If so, I'm not sure what dimFeetSelector would return. Is it an HTMLElement object? Or another jQuery object? The jQuery object defines its own prototype that does not include a hasOwnProperty method. However, it does have a "hasOwn" method (which is a reference to Object.prototype.hasOwnProperty). So if dimFeetSelect is a jQuery object, then you can probably call hasOwn instead of hasOwnProperty (though it doesn't explain why it would work in Chrome).