get 2 vales after decimal

Math.round(77.888555*100)/100 ;

var n=77.888555;
alert(truncate(n));

function truncate(num) 
{
	var returnValue=num.toString();
	var pos = returnValue.indexOf(".");	
	if ( pos == -1 )
             {
		return returnValue + ".00";
             }
	else
	{
		returnValue += "00";	
		return returnValue.substr(0,pos+3);
	}
}

number.toFixed(x);