function compute(calc) {
          var D = document.getElementById("calc");
	  var H = document.getElementById("highlight");
          var cape = D.cape.value;
          var wmax = D.wmax.value;
          var ehi = D.ehi.value;
          var sspd = D.sspd.value;
          var srh = D.srh.value;
          var result1 = 4.943709-(0.000777*cape)-(0.004005*wmax)+(0.181217*ehi)-(0.026867*sspd)-(0.006479*srh);
          var result = Round(result1,2);
          
          if ((D.cape.value == 0) && (D.wmax.value == 0) && (D.ehi.value == 0)) {
            D.result.value="Enter Values";
            H.type[0].checked=false;
          } else {
            D.result.value=result;}
            if (result >= 3.5) {H.type[0].checked=true;}
            if ((result > 2.5) && (result < 3.5)) {H.type[1].checked=true;}
            if ((result > 1.5) && (result < 2.5)) {H.type[2].checked=true;}
            if (result <= 1.5) {H.type[3].checked=true;
          }
        }
        function erase(calc) {
          var D = document.getElementById("calc");
	  var H = document.getElementById("highlight");
          D.cape.value = "";
          D.wmax.value = "";
          D.ehi.value = "";
          D.sspd.value = "";
          D.srh.value = "";
          D.result.value = "";
          H.type[0].checked=false;
          H.type[1].checked=false;
          H.type[2].checked=false;
          H.type[3].checked=false;
        }
        function Round(num,precision) { 
          //convert num to string 
          num = "" + num;
          precision = parseInt(precision); 

          //convert desired result to integer
          //unwanted digits will be after the decimal point
          var fullNum = "" + Math.round(num* Math.pow(10, precision)); 

          //find decimal point should go 
          var decPoint = fullNum.length - precision; 

          if (decPoint != 0) { 
            //concatenate left and right part of the decimal together 
            result = fullNum.substring(0, decPoint); 
            result += "."; 
            result += fullNum.substring(decPoint, fullNum.length); 
          } else { 
            result = fullNum; 
          } 
          return result; 
        }