Created with Copy to Gist

RoundToHalf.js

function roundToHalf(value) { 
   var converted = parseFloat(value); // Make sure we have a number 
   var decimal = (converted - parseInt(converted, 10)); 
   decimal = Math.round(decimal * 10); 
   if (decimal == 5) { return (parseInt(converted, 10)+0.5); } 
   if ( (decimal < 3) || (decimal > 7) ) { 
      return Math.round(converted); 
   } else {
      return (parseInt(converted, 10)+0.5); 
   } 
}