function isInteger( x ) {
	return (floor(x) === x);
}
Tests if a finite double-precision floating-point number is an integer.

@param {number} x - value to test
@returns {boolean} boolean indicating whether the value is an integer

@example
var bool = isInteger( 1.0 );
// returns true

@example
var bool = isInteger( 3.14 );
// returns false