function forward() {
      with (document.convert) {
	 unit1.value = unit1.value.toString().replace(/[^\d\.eE-]/g,'');
	 if (unit1.value*2.20462262185 != 0)
	    unit2.value = unit1.value*2.20462262185;
      }
   }
   function backward() {
      with (document.convert) {
	 unit2.value = unit2.value.toString().replace(/[^\d\.eE-]/g,'');
	 if (unit2.value/2.20462262185 != 0)
	    unit1.value = unit2.value/2.20462262185;
      }
   }