Simples solução para remover e adicionar elementos em um array.

array_functions.js

/**
 * Remove array element.
 */
Array.prototype.rm = function(value)
{
	var arrays_s = this;
	for( var i=0; i<this.length; i++)
	{
		var obj = this[i];
		if( typeof obj === 'number' && obj == value )
			this.splice(i, 1);
	}//for
	
	return this;
}//function

/**
 * Adds array element.
 */
Array.prototype.add = function(value)
{
	var pos = 0, exist = false;
	for( var i =0; i< this.length; i++ )
	{
		var obj = this[i];
		if( typeof obj === 'number' && obj == value )
		{
			pos = i;
			exist = true;
		}//if
	}//for
	
	if( !exist )
		this.push(value);
	return this;
	
}//function