34,333
edits
Changes
→Arithmetic Operators
<td>%<td>Modulus - Divides left hand value by right hand value and returns remainder</td>
</table>
=== Incrementing and Decrementing Values ===
In JavaScript programming it is extremely common to need to incremement and decrement values assigned to variables. The long handed way fo doing this would be:
<pre>
x = 10;
x = x - 1; // Decreases value of x by 1
x = x + 1; // Increase value of x by 1
</pre>
A quicker way to perform this is to use the ++ and -- operators. The syntax for this is as follows:
<pre>
--x; // Decreases value of x by 1
++x; // Increase value of x by 1
</pre>
These operators can also be used increment and decrement a value after an expression as been performed. Suppose you have a varable ''x'' which has been assigned a value of 5. You want to add the value of x to a varable called y and then decrement x by 1. One way to do this is as follows:
<pre>
var x = 5;
var y = 10;
y = y + x; // assigns the value 15 to variable y
++x; // adds 1 to x to make it 6
</pre>
By placing the operator after the variable name the variable is automatically incremented or decremented immediately after the expression as been evaluated:
<pre>
var x = 5;
var y = 10;
y = y + x++; // value of y is now 15, value of x is now 6
// Note that the above exression can be further shortened as follows:
y += x++ // value of y is now 15, value of x is now 6
</pre>
