What is the difference between using call and apply to invoke a function? var func = function() { alert('hello!'); }; func.apply(); vs func.call(); Are there performance differences between the two aforementioned methods? When is it b...I'm writing a Chrome extension that involves doing a lot of the following job: sanitizing strings that might contain HTML tags, by converting <, > and & to <, > and &, respectively. (In other words, the same as...
What kinds of activities will trigger reflow of web page with DOM? It seems there are different points of view. According to http://www.nczonline.net/blog/2009/02/03/speed-up-your-javascript-part-4/, it happens When you add or remove a DOM node...
How do parseInt() and Number() behave differently when converting strings to numbers?...
From the MDN docs for the standard setPrototypeOf function as well as the non-standard __proto__ property: Mutating the [[Prototype]] of an object, no matter how this is accomplished, is strongly discouraged, because it is very slow and unavo...
I ran this code and got the below result. I curious to know why [] is faster? console.time('using[]') for(var i=0; i<200000; i++){var arr = []}; console.timeEnd('using[]') console.time('using new') for(var i=0; i<200...I learned from books that you should write for loop like this? for(var i=0, len=arr.length; i < len; i++){ // blah blah } so the arr.length will not be calculated each time. Others say that the compiler will do some optimization to thi...Is there a good profiler for javascript? I know that firebug has some support for profiling code. But I want to determine stats on a longer scale. Imagine you are building a lot of javascript code and you want to determine what are actually the bot...
I have a model with possibly thousands of objects. I was wondering what would be the most efficient way of storing them and retrieving a single object once I have it's id. The id's are long numbers. So these are the 2 options I was thinkin...
What's the fastest way to count the number of keys/properties of an object? It it possible to do this without iterating over the object? i.e. without doing var count = 0; for (k in myobj) if (myobj.hasOwnProperty(k)) count++; (Firefox did...
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