Question

I want to know the how to handle when user press up arrow when focused on a textbox

Answer 1

$("input_selector").focus(function(){
    $(this).bind("keyup", function(e){
         if ( e.keyCode == 39){
              //do what you want with the up arrow
         }
    });
});

$("input_selector").blur(function(){
    $(this).unbind("keyup");
});