How to concatenate variables in javascript?

Question

I am trying to concatenate variables in inside a function and then return. In php we just put a period before the "=" but it is not working in javascript.

Can someone please help me figure this one out?

function NewMenuItem(){
    var output = "<input type='checkbox'> ";
    var output .= "<input type='text'> ";

    return output;
}

use the + operator: "some string" + "some other string", Expressions and Operators — Patrick Evans
– Patrick Evans, Commented Sep 12, 2014 at 19:23
You'll benefit from giving the MDN introduction to JavaScript a read-through. Especially if you already know another language, read through it so you know the syntax differences. — Mike 'Pomax' Kamermans
– Mike 'Pomax' Kamermans, Commented Sep 12, 2014 at 19:24

agconti · Accepted Answer · 2014-09-12 19:24:15Z

3

The + operator will concatenate two strings, ie. "Hello" + " World" //> "Hello World". Using += is a short cut for assigning and concatenating a variable with its self.

ie. instead of:

var myVar = "somestring";
myVar = myVar + "another String";

you can just do:

var myVar = "somestring";
myVar += "another String";

For your problem:

function NewMenuItem() {
    //This is just a small example. The end result is more broader then this
    var output = "<input type='checkbox'> ";
    output += "<input type='text'> ";
    return output;
} //end of NewMenuItem(){

answered Sep 12, 2014 at 19:24

agconti

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3 Comments

agconti Over a year ago

@torazaburo true, I guess thats just out of habit from the days of arithmetic. Updated.

eldan221 Over a year ago

agconti. Thank for the reply My mistake was that i was doing var output = "<input type='checkbox'> "; var output += "<input type='text'> "; I put a var after the second variable. But your example worked. Thanks!

agconti Over a year ago

@eldan221 if I answered your question can you please accept my answer?

Santiago Nicolas Roca · Accepted Answer · 2014-09-19 17:12:59Z

1

"+=" is the standard way to concatenate in javascript;

var a = "yourname";
var b = "yourlastname";
var name = a + b;
var complete_name = "my name is: ";
complete_name += name;

result : my name is: yourname yourlastname

edited Sep 19, 2014 at 17:12

user663031

answered Sep 12, 2014 at 19:25

Santiago Nicolas Roca

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2 Comments

Matt Burland Over a year ago

You can't use += on a variable that is undefined. Your code doesn't even compile.

Santiago Nicolas Roca Over a year ago

thanks i didnt see that basic error. Edited my answer.

Academia · Accepted Answer · 2014-09-12 19:28:21Z

0

With Concat function or with plus operator (+).

Check this link jsfiddle to see a working example.

answered Sep 12, 2014 at 19:28

Academia

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1 Comment

user663031 Over a year ago

concat function is deprecated/reccommnded against.

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