String operators (JavaScript)

String operators concatenate values.

The string operators are as follows:


Operator	Description
`string1 + string2`	Concatenates `string1` and `string2` so the beginning character of `string2` follows the ending character of `string1`.
`string1 += string2`	Concatenates `string1` and `string2`, and assigns the result to `string1`.

Usage

The plus operator means concatenation if either of the operands is a string. For example,

"foo"
+ 5 + 1

means "foo51", while

"foo"
+ (5 + 1)

means "foo6". Best practice is to parenthesize non-string expressions within string expressions.

Examples

This example concatenates two string variables.

function p(stuff) {
	print("<<<" + stuff + ">>>");
}

var f = "foo";
var b = "bar";
p(f + " " + b); // "foo bar"

This example concatenates two string variables and assigns the result to a variable.

function p(stuff) {
	print("<<<" + stuff + ">>>");
}

var f = "foo";
var b = "bar";
var fb = f;
fb += " ";
fb += b;
p(fb); // "foo bar"

This example demonstrates how numeric values are concatenated with strings.

function p(stuff) {
	print("<<<" + stuff + ">>>");
}

var f = "foo";
var n = 5;
p(f + n); // foo5
p(5 + f); // 5foo
p(f + n + 1); // foo51
p(f + (n + 1)); // foo6