Is a number whole? and Is a number a multiple of x?

[techno_race]

Here are a couple functions I keep using to validate numbers.
Is a number whole?

function isWhole(x)
{
	var number = x;
	var rounded = Math.round(number);
	if (number == rounded)
	{
		//What do do if the number is whole
	}
	else
	{
		//What to do if the number is not whole
		//or the number is not a number
	}
}

Just replace the commented lines with useful code.
I find it extremely useful to use something like return "The number was whole.";
This way, you can use <? echo 'var input = '.$_GET['input'].';'; ?>
var result = isMultiple(input);
To call this function, use:

isMultiple(number)

Is a number a multiple of x?
This is a little trickier.

function isMultiple(y,z)
{
	var dividee = y;
	var divider = z;
	var divided = dividee / divider;
	var dividem = Math.round(divided);
	if (divided == dividem)
	{
		//What do do if the number is a multiple
	}
	else
	{
		//What to do if the number is not a multiple
		//or the number is not a number
	}
}

Do the same with the commented code.
To call this one, use:

isMultiple(number,is_a_multiple_of_?)

(is_a_multiple_of_? should be the number to check if number is a multiple of.)

[mburt]

For the whole thing, I'm assuming this is easier:

Number.prototype.whole = function() { return this.toString().indexOf(".") > -1 ? false : true; }

Usage:

var num = 4.5294;
if (num.whole()) {
  //do something
} else {
  //do something else
}

[mburt]

In addition:

Number.prototype.multipleOf = function(x) { return (x / this).whole() ? true : false; }

[mburt]

Update:

Number.prototype.multipleOf = function(x) { return (x/this).whole() ? (arguments[1] ? (x/this) : true) : false; }

Optional flag, which returns the remainder.

[techno_race]

Who said it wasn't?
Mine would be easier for beginner coders to understand.
Which is pretty much the point.
Go figure.

[mburt]

Once again updated, I forgot to include the arguments[1] for the false:

Number.prototype.multipleOf = function(x) { return arguments[1] ? this/x : ((this/x).whole() ? true : false); }

[mburt]

Well the readers don't need to know what's going on, I just think:

(x).whole();

and

(x).multipleOf(y);

are easy to use.

[mburt]

Oops... I had my variables mixed up too:

Number.prototype.multipleOf = function(x) { return arguments[1] ? x/this : ((x/this).whole() ? true : false); }

[Twey]

Number.prototype.isMultipleOf(x) {
  return !(this % x);
};

Number.prototype.isWhole() {
  return this.isMultipleOf(1);
};

... of course actually bothering to write functions for these starts to seem a little silly...

[mburt]

Lol, I KNEW you would come along and do that (another way of writing the function). But I see what you're saying, they are really simple.