I used to take pride in my short, bulletproof and elegant String and Number type checks:
// Check whether obj is a Number obj + 0 === obj // Check whether obj is a String obj + '' === obj
I always thought that apart from being short and elegant, they should be faster.
However, some quick tests gave me a cold slap in the face and proved my assertion to be entirely false.
You probably know about Firebug Lite, but this either requires you to already have the bookmarklet, or include the script in the page. Although Firebug Lite is a great tool for more in depth debugging, it can be tedious for simple tasks (eg. “What’s the value of that property?”).
Fortunately, there is a simpler way.
Recently, PPK stated that he hates Google Chrome’s automatic updates. I disagree. In fact, I think that all browser vendors should enforce automatic updates as violently as Google Chrome does. There should be no option to disable them. For anybody.
UPDATE: New version
First of all, happy Valentine’s day for yersterday. 🙂 This is the second part of my “Using CSS3 today” series. This article discusses current RGBA browser support and ways to use RGBA backgrounds in non-supporting browsers. Bonus gift: A PHP script of mine that creates fallback 1-pixel images on the fly that allow you to easily utilize RGBA backgrounds in any browser that can support png transparency. In addition, the images created are forced to be cached by the client and they are saved on the server’s hard drive for higher performance.
As you probably know already, when browsers implement an experimental or proprietary CSS property, they prefix it with their “vendor prefix”, so that 1) it doesn’t collide with other properties and 2) you can choose whether to use it or not in that particular browser, since it’s support might be wrong or incomplete.
Instead of iterating over all possible vendor prefixes every time to test if a prefixed version of a specific property is supported, we can create a function that returns the current browser’s prefix and caches the result, so that no redundant iterations are performed afterwards. How can we create such a function though?
Math.floor are very useful functions. However, when using them, I find myself many times needing to specify a precision level. You don’t always want to round to an integer, you often just want to strip away some of the decimals.
We probably all know that if we have a function to round to integers, we can round to X decimals by doing
Math.pow(10,X). This kind of duck typing can get tedious, so usually, you roll your own function to do that. However, why not just add that extra functionality to the functions that already exist and you’re accustomed to?