HTML and CSS Reference
In-Depth Information
Where Does JavaScript Go and Why?
Because we will create the programming logic for the Canvas in JavaScript, a question arises:
where does that JavaScript go in the pages we have already created?
It's a good idea to place your JavaScript in the <head> of your HTML page because it makes
it easy to find. However, placing JavaScript there means that the entire HTML page needs to
load before your JavaScript can work with the HTML. This also means that the JavaScript
code will start to execute before the entire page loads. As a result, you will need to test to see
whether the HTML page has loaded before you run your JavaScript program.
There has been a recent move to put JavaScript right before the </body> at the end of an
HTMLdocumenttomakesurethatthewholepageloadsbeforetheJavaScriptruns.However,
because we are going to test to see whether the page has loaded in JavaScript before we run
our <canvas> program, we will put our JavaScript in the traditional <head> location. If you
are not comfortable with this, you can adapt the style of the code to your liking.
No matter where you put the code, you can place it inline in the HTML page or load an ex-
ternal .js file. The code for loading an external JavaScript file might look like this:
< script type = "text/javascript" src = "canvasapp.js" >< /script>
To make things simple, we will code our JavaScript inline in the HTML page. However, if
you know what you are doing, saving an external file and loading it will work just as well.
NOTE
In HTML5, you no longer have to specify the script type.
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