Feature Sensing

Test if the browser supports a specific JavaScript Feature directly, do not test whether the browser was one that did or didn't support that feature ten years ago.

Right from day one JavaScript has provided a simple way to check whether the version of JavaScript currently being run supports a given object, method or function. The same (or similar code) can also be used to check if a property or variable exists. Using this way of testing if the browser supports your script your script will always work in new browsers that add that support even where the prior version didn't.

Feature Sensing