jQuery.extend(Array.prototype, {
	sum:function() {
		var key, sum = 0;
		if(typeof this !== 'object') { return null; }
		for(key in this) { if(!isNaN(this[key])) { sum +=(this[key] * 1); } }
		return sum;
	},
	contains:function(needle) {
		var key = '', counter = 0;
		for(key in this) {
			if(this[key] == needle) { return counter; }
			counter++;
		}
		return false;
	},
	keyExist:function(needle) {
		var key = '';
		for(key in this) {
			if(key == needle) { return key; }
		}
		return false;
	},
	put:function(separator) {
		if (this.length == 0) { return this; }
		switch (separator) {
			case '][' : return "["+this.join("][")+"]"; break;
			case '}{' : return "{"+this.join("}{")+"}"; break;
			case ')(' : return "("+this.join(")(")+")"; break;
		}
	}
});