+= javascript What does it mean?

D

dllll

Registered Member

Jun 20, 2014

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• Oct 20, 2014

• #1

Im learning javascript and im confused on what this means +=
I know the + is concatenation and = is equals but im still confused, i looked it up of course on w3schools but im still confused lol?
Its being used between 2 variables on the code im editing.

 

Gogol

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Sep 10, 2010

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• Oct 20, 2014

• #2

That's for appending value to a variable...

example..

Code:

var1 = 'a';
var1 += 'b';
alert(var1)
// var1 will now become ab

it is essentially the same code as

Code:

var1 = 'a';
var1 = var1+ 'b';
alert(var1);
//var1 will now become ab

 

D

dllll

Registered Member

Jun 20, 2014

89

39

• Oct 20, 2014
• Thread Starter Thread Starter

• #3

Thanks i understand it now

 

Repulsor

Senior Member

Jun 11, 2013

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• Oct 20, 2014

• #4

g0g0l cleared it up for you.

Just FYI its .= in php.

Adds something to the existing value of the variable.

 

jazzc

Elite Member

Jan 27, 2009

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13,447

• Oct 20, 2014

• #5

Note that if your variables are numbers, it's an shorthand for addition.

Code:

var a=1,b=2;
b += a; // => 3
// Same as b = b + a;

Just remember this: for strings + is concatenation and for numbers it's addition. This is called operator overloading (same operator acts differently depending on the operand types).