var browser=(((navigator.appName=="Netscape")&&(parseInt(navigator.appVersion)>=4))||
((navigator.appName=="Microsoft Internet Explorer")&&(parseInt(navigator.appVersion)>=4)))

if (browser) {
        var theweight=0.0;
        var thegravity=0.0;
        var thevolume=0.0;
        var check1 = 0;
        var check2 = 0;
        var check3 = 0;
        var check = 0;
}

function currency(anynum) {
        //returns number as string in $xxx,xxx.xx format.
        anynum = "" + eval(anynum)  //evaluate (in case an expression sent)
        intnum = parseInt(anynum)  //isolate integer portion
        intnum = Math.abs(intnum)
        intstr = ""+intnum
        //add comma in thousands place.
        if (intnum >= 1000) {
                intlen = intstr.length
                temp1=parseInt(""+(intnum/1000))
                temp2=intstr.substring(intlen-3,intlen)
                intstr = temp1+","+temp2

        }
        if (intnum >= 1000000) {
                intlen = intstr.length
                temp1=parseInt(""+(intnum/1000000))
                temp2=intstr.substring(intlen-7,intlen)
                intstr = temp1+","+temp2

        }

        decnum = Math.abs(parseFloat(anynum)-parseInt(anynum)) //isolate decimal portion
        decnum = decnum * 100 // multiply decimal portion by 100.
        decstr = "" + Math.abs(Math.round(decnum))
        if (decstr.length>2) {decstr=decstr.substring(0,2)}
        while (decstr.length < 2) {decstr="0"+decstr}
        retval = intstr + "." + decstr 
        if (anynum < 0) {
                retval="("+retval+")"
        }
        return retval
}






function ComputeWeight(){

	check1 = 0;
	check2 = 0;
	check3 = 0;
	check = 0;

	if (document.forms[0].elements[0].value == "") {check1 = 1;}
	if (document.forms[0].elements[1].value == "") {check2 = 1;}
	if (document.forms[0].elements[2].value == "") {check3 = 1;}
	
	if ((check1 == 1) && (check2 ==1)) {check = 1;}
	if ((check1 == 1) && (check3 ==1)) {check = 1;}
	if ((check2 == 1) && (check3 ==1)) {check = 1;}
	
	if (check == 1) {
	 	alert ("You have not entered enough values to complete the computation!");
	} else if (document.forms[0].elements[2].value == ""){
			theweight = document.forms[0].elements[0].value;
        		thegravity = document.forms[0].elements[1].value;
        		thevolume = currency(theweight * thegravity);
        		document.forms[0].elements[2].value = thevolume; 
  		} else if (document.forms[0].elements[1].value == "") {
  		         	theweight = document.forms[0].elements[0].value;
  		         	thevolume = document.forms[0].elements[2].value;
  		         	thegravity = currency(thevolume / theweight);
  		         	document.forms[0].elements[1].value = thegravity;	        	
   			} else if (document.forms[0].elements[0].value == "") {
   		       	         	thegravity = document.forms[0].elements[1].value;
   		       		  	thevolume = document.forms[0].elements[2].value;
   		        	 	theweight = currency(thevolume / thegravity);
   		        	 	document.forms[0].elements[0].value = theweight;
   				}
}