function heat1_c(HI1_C){
  if(parseFloat(HI1_C.tempair.value) < 20){
    alert("La temperatura ha de tenir un valor igual o superior a 20º");
   }
   else {									
         var comment = '';
         T= parseFloat(HI1_C.tempair.value);
         H = parseFloat(HI1_C.RHumidity.value);
         t=7.5*T/(237.7+T);
         et=Math.pow(10,t);
         e=6.112*et*(H/100);
         humidex=T+(5/9)*(e-10);
         if (humidex < T)
         {
          humidex=T;
         }
         comment += humidex;
					
         HI1_C.heatindex.value =  Math.round(comment);		
        }								
}
			       

function clearHI1_C(form){
   form.tempair.value = "";
   form.RHumidity.value = "";
   form.heatindex.value = "";
}