How to make a javaScript variable equal to something or something else? [duplicate]

Question

Trying to add randomness to which image is displayed. Issue with saying calling and or statement.

var image = url3 | url2 | url1;
    buildImage(image);



function buildImage(imagesrc) {
    var img = document.createElement('img');
    img.src = imagesrc;
    document.getElementById('content').appendChild(img);

You have a very confused understanding of what OR means in programming. It's not how you make a collection of things, it's a boolean or binary operation. — Barmar
– Barmar, Commented Aug 29, 2014 at 0:50
@Barmar In fairness, if this was SML, datatype image = url1 | url2 | url3 would be perfectly valid. — Patrick Collins
– Patrick Collins, Commented Aug 29, 2014 at 0:52

Amadan · Accepted Answer · 2014-08-29 00:49:30Z

2

var images = [url3, url2, url1];
var image = images[(Math.random() * images.length)|0];

The "or" operators are not probabilistic "or" that will return one value or another. They are very specific: || will return the first value unless it's falsy, in which case it returns the second; and | converts both arguments to integers and applies the same operation to each individual binary digit.

answered Aug 29, 2014 at 0:49

Amadan

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Overv · Accepted Answer · 2014-08-29 00:49:44Z

1

Instead of using separate variables, make a urls array:

var urls = [
    "http://example.com/img1.jpg",
    "http://example.com/img2.jpg",
    "http://example.com/img3.jpg"
];

You can then select a random URL by doing:

var url = urls[Math.floor(Math.random() * urls.length)];

And call buildImage:

buildImage(url);

answered Aug 29, 2014 at 0:49

Overv

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