这是我正在寻找的最接近的 jsFiddle

Here is the closest to what I'm looking for jsFiddle

 $('#textbox').keydown(function(event){
    var keycode = (event.keyCode ? event.keyCode : event.which);
    $('#keydownCode').html(keycode);


 if(keycode == 144){
    $('#Typoef').html('It is a Sell');
     //perform Sell operation here
 }
 else if(keycode == 109){
    $('#Typoef').html('It is a Purchase');
     //perform Purchase operation here
 }
 else if(keycode == 35){
    $('#textbox').val($('#textbox').val()+"1");
     e.preventDefault();
 }
 else if(keycode == 40){
    $('#textbox').val($('#textbox').val()+"2");
     e.preventDefault();
 }
 else if(keycode == 34){
    $('#textbox').val($('#textbox').val()+"3");
     e.preventDefault();     
 }
 else if(keycode == 37){
     $('#textbox').val($('#textbox').val()+"4");
     e.preventDefault(); 
 }
 else if(keycode == 12){
    $('#textbox').val($('#textbox').val()+"5");
     e.preventDefault();     
 }
 else if(keycode == 39){
    $('#textbox').val($('#textbox').val()+"6");
     e.preventDefault();     
 }
 else if(keycode == 36){
    $('#textbox').val($('#textbox').val()+"7");
     e.preventDefault();     
 }
 else if(keycode == 38){
    $('#textbox').val($('#textbox').val()+"8");
     e.preventDefault();     
 }else if(keycode == 33){
    $('#textbox').val($('#textbox').val()+"9");
     e.preventDefault();     
 }
 else if(keycode == 45){
    $('#textbox').val($('#textbox').val()+"0");
     e.preventDefault();     
 }
 else{
     $('#Typoef').html('');
 }
});