function update(form) {
if (form.xparm[0].checked) { form.xparmunit.value = "kg/cu m"}
else {form.xparmunit.value = "%"}
}

function check(form) {

if (form.xparm[0].checked && (form.xparmvalue.value < 15)) { 
   form.xparmvalue.value = 16
   alert("concentration must be greater than 15")
return false; }

if (form.xparm[0].checked && (form.xparmvalue.value > 280)) { 
   form.xparmvalue.value = 279
   alert("concentration must be less than 280")
return false; }

if (form.xparm[1].checked && (form.xparmvalue.value < 2)) { 
   form.xparmvalue.value = 3
   alert("concentration must be greater than 2")
return false; }

if (form.xparm[1].checked && (form.xparmvalue.value >= 24)) { 
   form.xparmvalue.value = 23
   alert("concentration must be less than 24")
return false; }

if (form.temperature.value < 10){   
   form.temperature.value = 10
   alert("temperature must be greater than 10")
return false; }

if (form.temperature.value > 90){   
   form.temperature.value = 90
   alert("temperature must be less than 90")
return false; }


}