function convertform(form){
    var firstvalue = 0;
    for (var i = 1; i <= form.count; i++) {
       // Find first non-blank entry
       if (form.elements[i].value != null && form.elements[i].value.length != 0) {
          if (i == 1 && form.elements[2].value != "") return false;
          firstvalue = form.elements[i].value / form.elements[i].factor;
          break;
       }
    }
    if (firstvalue == 0) {
       clearform(form);
       return false;
    }
    for (var i = 1; i <= form.count; i++)
       form.elements[i].value = formatvalue((firstvalue * form.elements[i].factor), form.rsize);
    return true;
}

function formatvalue(input, rsize) {
   var invalid = "**************************";
   var nines = "999999999999999999999999";
   var strin = "" + input;
   var fltin = parseFloat(strin);
   if (strin.length <= rsize) return strin;
   if (strin.indexOf("e") != -1 ||
       fltin > parseFloat(nines.substring(0,rsize)+".4"))
      return invalid.substring(0, rsize);
   var rounded = "" + (fltin + (fltin - parseFloat(strin.substring(0, rsize))));
   return rounded.substring(0, rsize);
}
function resetform(form) {
    clearform(form);
    form[1].value = 1;
    convertform(form);
    return true;
}
function clearform(form) {
    for (var i = 1; i <= form.count; i++) form[i].value = "";
    return true;
}

document.forms[0].count = 5;  // number of unit types
document.forms[0].rsize = 7;  // Rounding size, use same as SIZE
document.forms[0].val1.factor = 10;            // mm to mm.
document.forms[0].val2.factor = 0.3937007874;  // mm to in.
document.forms[0].val3.factor = 0.01;  // mm to mtr.
document.forms[0].val4.factor = 0.03280839895;  // mm to feet.
document.forms[0].val5.factor = 0.01093613298; //mm to yards.

document.forms[1].count = 2;
document.forms[1].rsize = 6;
document.forms[1].val1.factor = 1;
document.forms[1].val2.factor = 2.2046215;

document.forms[2].count = 3;
document.forms[2].rsize = 6;
document.forms[2].val1.factor = 0.980665;
document.forms[2].val2.factor = 1;
document.forms[2].val3.factor = 14.22;

document.forms[3].count = 4;
document.forms[3].rsize = 6;
document.forms[3].val1.factor = 1;
document.forms[3].val2.factor = 33.8239926;
document.forms[3].val3.factor = 1.056998;
document.forms[3].val4.factor = 0.2642499;