Why is null considered an object in JavaScript? Is checking if ( object == null ) Do something the same as if ( !object ) Do something ? And also: What is the difference between null and undefined?...
In my particular case: callback instanceof Function or typeof callback == "function" does it even matter, what's the difference? Additional Resource: JavaScript-Garden typeof vs instanceof...
Is there a better way to get the type of a variable in JS than typeof? It works fine when you do: > typeof 1 "number" > typeof "hello" "string" But it's useless when you try: > typeof [1,2] "object"...
I have a window, where before being closed I refresh the underlying page. if(opener && typeof(opener.Refresh) != 'undefined') { opener.Refresh(); } If I moved away from the original opening page, this code would throw a "Pe...
Is there anyway to detect if a JavaScript object is a regex? For example, I would like to do something like this: var t = /^foo(bar)?$/i; alert(typeof t); //I want this to return "regexp" Is this possible? Thanks! EDIT: Thanks for all t...
One can use typeof to determine whether a value is primitive or boxed. Consider: typeof "foo"; // "string" typeof new String("foo"); // "object" In combination with Object.prototype.toString we could define the fo...
I'm trying to use some of the more advanced OO features of Javascript, following Doug Crawford's "super constructor" pattern. However, I don't know how to set and get types from my objects using Javascript's native type system...
In this question I did not see suggestions to use constructor. So instead of typeof callback == "function" I would use callback && (callback.constructor==Function). To me it seems obvious that comparison to memory pointers is alway...
I have a flash object (HTMLObjectElement) created (with jQuery) and added it to the DOM. That is working OK in all browsers. This object is saved/stored in a variable called "o.data.cam". Other functions checking this variable if it is valid....
I thought this would be as easy as: if(typeof(Array.push) == 'undefined'){ //not defined, prototype a version of the push method // Firefox never gets here, but IE/Safari/Chrome/etc. do, even though // the Array object has a push metho...
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