function roundFixed(num, fixed) {

     var pos = num.toString().indexOf('.'),

         decimal_places = num.toString().length - pos - 1,

         _int = num * Math.pow(10, decimal_places),

         divisor_1 = Math.pow(10, decimal_places - fixed),

         divisor_2 = Math.pow(10, fixed);

     return Math.round(_int / divisor_1) / divisor_2;

 }

 console.log(roundFixed(3.135,2));//-> 3.14

 console.log(roundFixed(2.135,2));//-> 2.14

 console.log(roundFixed(0.955,1));//-> 1

 console.log(roundFixed(0.955,2));//-> 0.96

 console.log(roundFixed(1.955,2));//-> 1.96

 console.log(roundFixed(1.955,1));//-> 2