JavaScript - Loop around properties of a textbox

var allprops="";
 var count = 0;
 for (var prop in RangeFromTextbox)
 {
     allprops += prop + "=" + RangeFrom[prop] + " \n" ;
     if (count > 20)
     {
         alert(allprops);
         allprops = "";
         count = 0;
     }
     count++;
 }
 alert(allprops);