Change an image when input is given

Question

I have a small basic html code with JavaScript . All I want is when I type 3,it should show me an image as specified and for 9 accordingly. This is the demo. Visit http://jsbin.

Answer 1

Try this

$(document).ready(function(){

var num2img = {
  "3":"visa",
  "9":"mastercard"
};

    $('#num').keyup(function(){
      var val = this.value;
      if(val.length<=1){
         var n = this.value.charAt(0);
         if(val && num2img[n]!==undefined){
           $('#cardImage')[0].src = 'http://placehold.it/100x100/eee&text='+ num2img[n] +'.png';
         }else{
           $('#cardImage')[0].src = 'http://placehold.it/100x100/cf5';
         }
      }
    });
});

DEMO