function calculate()
{

	var count = 20;
	var factor = new Array();
	factor[1]=1; 			//sq.ft
	factor[2]=0.0930000000000000000;//sq.mts
	factor[3]=0.1111111111111000000;//sq.yards
	factor[4]=0.0000229566300000000;//acres
	factor[5]=0.0000092904166000000;//hectares
	factor[6]=0.0000573921030000000;//bigha1
	factor[7]= 0.000002869605100000;//biswa1
	factor[8]= 0.000036730946000000;//bigha2
	factor[9]= 0.000001836547300000;//biswa2
	factor[10]= 0.00138888890000000;//kottah
	factor[11]= 0.00000926059690000;//kanal
	factor[12]= 0.00018521194000000;//marla
	factor[13]= 0.00041666667000000;//ground
	factor[14]= 0.00229600000000000;//cent
	factor[15]= 0.01389088900000000;//aankadam
	factor[16]= 0.00367242010000000;//perch
	factor[17]= 0.00009181050300000;//rood
	factor[18]= 0.00091827364554640;//guntha
	factor[19]= 0.002222222222222223;//chatak
	factor[20]= 0.00092936802973000;//are

	var element =  new Array();
	element[1] = "Sq Ft";
	element[2] = "Sq Mts";
	element[3] = "Sq Yards";
	element[4] = "Acres";
	element[5] = "Hectares";
	element[6] = "Bigha I";
	element[7] = "Biswa I";
	element[8] = "Bigha II";
	element[9] = "Biswa II";
	element[10] = "Kottah (B)";
	element[11] = "Kanal";
	element[12] = "Marla";
	element[13] = "Grounds";
	element[14] = "Cents";
	element[15] = "Aankadam";
	element[16] = "Perch";
	element[17] = "Rood";
	element[18] = "Guntha";
	element[19] = "Chataks";
	element[20] = "Ares";

        
        var value = document.getElementById("form1:valueField").value;
        var parsecheck=""+parseFloat(value);
        if(parseFloat(value)==0 || parsecheck=="NaN")
        {
                document.getElementById("form1:resultST").value = "Please enter a valid value/number.";
                return ;
        }

        var fromId = document.getElementById("form1:fromDDList").value;
        var fromName = element[fromId];
        var fromFactor = factor[fromId];
        
        var toId = document.getElementById("form1:toDDList").value;
        var toName = element[toId];
        var toFactor = factor[toId];
        var result;
        if(fromId == toId)
        {
            result = value;
        }
        else
        {
            result = (toFactor * value) / fromFactor;
        }

        document.getElementById("form1:resultST").value = value + "   " + fromName + "   =   " + Math.round(result*10000)/10000 + "   " + toName;
}