Simple question: How to do variable concatenation in JavaScript?

Question

In php I can have something like this:

$animal = 'horse';

$animal += ', tigers';

then the value of animals would be "horse, tigers". How do I do this type of variable concatenation in JavaScript?

You could have tried it out yourself before asking it on SO. — Chandu, Dec 26 '10 at 01:50

Chandu · Answer 1 · 2010-12-26T01:56:30.710

1

var szTest = "";
szTest += "One";
szTest += ", Two";

edited Dec 26 '10 at 01:56

answered Dec 26 '10 at 01:49

Chandu

2

I want to downvote your hungarian (but I won't this time). Not only is hungarian out-dated in the first place, but javascript doesn't use zero-terminated strings, and thus your sz prefix is wrong. – Joel Coehoorn Dec 26 '10 at 01:51
@Joel, Systems Hungarian is outdated. Apps Hungarian can sometimes be useful. Another problem with this answer (and the question) is that this *isn't* how you do it in PHP. – Matthew Flaschen Dec 26 '10 at 01:55
@Joel agree completely, the sz makes every variable name look like some Hungarian guy's name. Ugh. – Rafe Kettler Dec 26 '10 at 02:01
And for the hungarian notation stuff Going thru this post: http://stackoverflow.com/questions/198825/best-way-to-get-rid-of-hungarian-notation – Chandu Dec 26 '10 at 02:28

Russell Dias · Answer 2 · 2010-12-26T06:03:53.343

1

In Javascript you can use the + to concatenate strings like so,

'horse' + ', tigers';

In PHP the string concatenation operator is .. So, your example should be:

$animal = 'horse';

$animal .= ', tigers';

edited Dec 26 '10 at 06:03

answered Dec 26 '10 at 01:49

Russell Dias

You can also use `+=` with roughly the expected effect (either way a new string is created). – Matthew Flaschen Dec 26 '10 at 01:51
@Matthew Flaschen Yes you can. The 'official' concatenation operator is the `.` as per the documentation. However, I will edit my post to reflect this. – Russell Dias Dec 26 '10 at 01:56
I wasn't clear. I meant you can use `+=` in **JavaScript**. If you do so in PHP, it will fail the same way `+` does (PHP will coerce the string to 0). – Matthew Flaschen Dec 26 '10 at 02:25
@Matthew Flaschen Oops, misinterpreted that. I should have tested it out anyway. Thanks for clearing it up. – Russell Dias Dec 26 '10 at 06:04

score 1 · Answer 3 · answered Dec 26 '10 at 01:50

1

Surprise:

'horse' + ', tigers'; // 'horse, tigers'

Now read a good tutorial before asking a thousand more questions:
https://developer.mozilla.org/en/JavaScript/Guide

answered Dec 26 '10 at 01:50

Ivo Wetzel

score 0 · Answer 4 · answered Dec 26 '10 at 01:49

0

var $animal = 'horse';

$animal += ', tigers';

answered Dec 26 '10 at 01:49

user113716

4 Answers4