forms - Trigger javascript function when any of multiple fields change (onchange) -

i have basic js knowledge.

i need trigger function below when of fields change in from. here works when var2 changes need triggered when of var# change. (i have 30 var @ end in form)

i think need have or condition, "if (var1.onchange or var2.onchange or ...) function()"

thanks in advance valuable input!

<script> window.onload = function () { var var0 = document.getelementbyid('field09')     var1 = document.getelementbyid('field10')     var2 = document.getelementbyid('field11')     storage = document.getelementbyid('field12')  var2.onchange= function()     {  storage.value = var0.value+" ; "+var1.value+" ; "+var2.value; }; }; </script> 

please try this:

window.onload = function () {     var var0 = document.getelementbyid('field09'),         var1 = document.getelementbyid('field10'),         var2 = document.getelementbyid('field11'),         storage = document.getelementbyid('field12'),          trigfunc = function(){              storage.value = var0.value + " ; " + var1.value + " ; " + var2.value;         }      var0.onchange = trigfunc;     var1.onchange = trigfunc;     var2.onchange = trigfunc; } 

demo: jsfiddle