<button> 0 </button>
     
<button> 1 </button>
     
<button> 2 </button>
     
<button> 3 </button>
     
<button> 4 </button>
     
 
     
<div id="log"></div>
     
 
     
<script>
     
var logDiv = $( "#log" );
     
 
     
for ( var i = 0; i < 5; i++ ) {
     
 $( "button" ).eq( i ).on( "click", { value: i }, function( event ) {
     
 var msgs = [
     
 "button = " + $( this ).index(),
     
 "event.data.value = " + event.data.value,
     
 "i = " + i
     
 ];
     
 logDiv.append( msgs.join( ", " ) + "<br>" );
     
 });
     
}
     
</script>
    
  
 
 

  

   
  
 
 

  

   

   When buttons are pressed:
   

   button = 0, event.data.value = 0, i = 5
button = 1, event.data.value = 1, i = 5
button = 2, event.data.value = 2, i = 5
button = 3, event.data.value = 3, i = 5
button = 4, event.data.value = 4, i = 5
   

   My question is why i=5 when each button is pressed?