Today I want to talk about some of the timing features of JavaScript. Every programming language has the ability to work with time in some fashion. JavaScript is no different. The first one I want to discuss is setTimeout(). The setTimeout() method calls a function or evaluates an expression after a set number of milliseconds. Let me digress for a moment on milliseconds as that is a bit odd for us humans to think through at first. Computers think in terms of milliseconds, while we humans think in terms of seconds as the shortest time frame (typically…unless you are running in the Olympic games). So we need to keep in mind that one (1) second is equal to one thousand (1000) milliseconds. This is important when we are working with timing functionality.
So…digression over…back to setTimeout(). Again, it runs a function or evaluates an expression. Let’s look at an example…
[code lang=”js”]
// Write a function that runs the setTimeout() method
function myTimeoutFunction() {
setTimeout(function(){alert("It works!")}, 3000);
}
[/code]
If we put the above code in a script tag and attach myTimeoutFunction to a button, then when we click that button, the setTimeout() method/function will run. So, it will alert the phrase “It works!” after three seconds.
So this can be a handy function to tap into to drive timing features of our programs. For example, you could build a game and after thirty seconds, disable it due to time running out.
Happy Coding!
Clay Hess
