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