Trying to display javascript number with commas

Question

<SCRIPT language="JavaScript">
    height = screen.height;
    width = screen.width;
    document.write( width*height + " pixels");
</SCRIPT>

I would like my answer to return with commas separating the numbers rather than one full number.

Please also note that Script doesn't have a "language" attribute — Jonathan, Jan 08 '14 at 18:52
Do you mean with a comma as in if width * height > 1000 you have a comma for thousand separator? — putvande, Jan 08 '14 at 18:52

Wayne · Accepted Answer · 2014-01-08T19:15:29.137

2

Here's a fun way to do it:

function format(num) {
    return ("" + num).split("").reverse().reduce(function(acc, num, i, orig) {
        return  num + (i && !(i % 3) ? "," : "") + acc;
    }, "");
}

format(777782374);

Prints:

"777,782,374"

Or, if you want to support decimals:

function format(num, fix) {
    var p = num.toFixed(fix).split(".");
    return p[0].split("").reduceRight(function(acc, num, i, orig) {
        var pos = orig.length - i - 1
        return  num + (pos && !(pos % 3) ? "," : "") + acc;
    }, "") + (p[1] ? "." + p[1] : "");
}

format(777782374, 4);

Prints:

"777,782,374.0000"

edited Jan 08 '14 at 19:15

answered Jan 08 '14 at 18:52

Wayne

59,728
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126

How can I apply that to my code? I'm still very new to javascript and I'm having trouble understanding the code. – Casualty Jan 08 '14 at 18:58
`format(width * height)` – Wayne Jan 08 '14 at 18:59
This doesn't seem to be working. Am I still missing something? – Casualty Jan 08 '14 at 19:04
You're not doing anything with the result. You really shouldn't be using `document.write` but just to get it working, do this: `document.write(format(width * height) + " pixels");` – Wayne Jan 08 '14 at 19:07
It still seems to be returning nothing. Here's a screenshot of the code: http://i.imgur.com/rck8WKA.jpg – Casualty Jan 08 '14 at 19:12
You're missing a paren after `height` – Wayne Jan 08 '14 at 19:13
Got it thanks. How would I make it display no decimal places? – Casualty Jan 08 '14 at 19:16
I updated the answer a bit. Either use the first function (that accepts no `fix` argument) or use the second version, but do not pass an argument for `fix`. – Wayne Jan 08 '14 at 19:19
Well done. Much appreciated! – Casualty Jan 08 '14 at 19:21

score 0 · Answer 2 · answered Jan 08 '14 at 18:50

0

Than you shouldn't multiply them?

document.write( width + ", " + height + " pixels");

answered Jan 08 '14 at 18:50

Jonathan

8,771
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OP is showing the total number of pixels. That's why the multiplication is needed. – cookie monster Jan 08 '14 at 18:54
What he said. I'm trying to display the total amount of pixels on your screen as a whole number, but with commas. Ex: 1920 x 1080 = 2073600. But I would like for it to say 2,073,600. – Casualty Jan 08 '14 at 19:01

Trying to display javascript number with commas

2 Answers2