[monolithed]

String.prototype.repeat = function(count) 
{
	if ((count |= 0 ) <= 0)
		throw new RangeError();

	var result = [];

	while (count--)
	    result.push(this);

	return result.join('');
};

var start = +new Date;

'foo'.repeat(1000000);

alert(+new Date-start);

String.prototype.repeat = function(count) 
{
	if ((count |= 0 ) <= 0)
		throw new RangeError();

	var result = '';

	while (count--)
	    result += this;

	return result;
};

var start = +new Date;

'foo'.repeat(1000000);

alert(+new Date-start);

String.prototype.repeat = function(count) 
{
	if ((count |= 0 ) <= 0)
		throw new RangeError();

	var result = '';

	while (count--)
	    result.concat(this);

	return result;
};

var start = +new Date;

'foo'.repeat(1000000);

alert(+new Date-start);

String.prototype.repeat = function(count) 
{
	if ((count |= 0 ) <= 0)
		throw new RangeError();

	return Array(count + 1).join(this);
};

var start = +new Date;

'foo'.repeat(1000000);

alert(+new Date-start);

String.prototype.repeat = function(count) 
{
	if ((count |= 0 ) <= 0)
		throw new RangeError();

	var result = '', 
            self = this;

	while (count)
	{
		if (count & 1)
			result += self;

		if (count >>= 1)
			self += self;
	}

	return result;
};

var start = +new Date;

'foo'.repeat(1000000);

alert(+new Date-start);

Тесты