myForm.attachEvent("onButtonClick", function(id){
var res, num1, num2;
num1 = parseInt(myForm.getItemValue("firstNum"));// returns the value of item
num2 = parseInt(myForm.getItemValue("secNum")); // returns the value of item
if (id=="plus") //defines addition
{ res=num1+num2;}
else if (id=="minus") //defines subtraction
{res=num1-num2;}
else if (id=="multiply")//defines multiplication
{res=num1*num2;}
else if (id =="divide")//defines division
{ if (num2==0) //if division by zero - generates a message
{alert("Error.Division by zero!");res="";}
else {res=num1/num2;}
}
myForm.setItemValue("resNum",res);// sets the value of item
})resNum receives the value does not update the database. Updates only when I type (form editing)