how to fire an event on textbox value change from pop window in MVC ASP.net

I m returning one value from pop up window now i want is the text box value changes from pop up window it should change its background color to red, otherwise no change will be reflect. What m i doing is

<input  type="button" id="button1" value="button1" style="width:95%;font-family:Verdana;font-size:9px;" onclick="window.open( '<%= Url.Action( "PopUp", "Home"  ) %>' ,'popup','height=410','width=200','target=popup','center','front');" onfocus="if(document.getElementById('HiddenVal').value!=null||document.getElementById('HiddenVal').value!=''){txtbutton.value=document.getElementById('HiddenVal').value ; document.getElementById('H开发者_开发百科iddenVal').value='';}" />

where txtbutton is text box and button1 is the button which open the pop up window. I want to change the color of text box if its value changed; otherwise its background should be white.

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remove your onfocus code from button and then place this code inside your js file.

$('#button1').focus(function(){
   if(document.getElementById('HiddenVal').value!=null&&document.getElementById('HiddenVal').value!=''){
        $('#txtbutton', window.parent.document).css("background-color","red"); //Assuming txtbutton is ID of your textbox
         document.getElementById('HiddenVal').value='';
   }
} );

one more way you can try is write a function inside your parent window and then call that function from child window-something like this-

<script> 
function ifDoneChild(val) {   
 $('#txtbutton').css("background-color","red");
} 
</script> 

call this function from child window-

 $('#button1').focus(function(){
           if(document.getElementById('HiddenVal').value!=null&&document.getElementById('HiddenVal').value!=''){
               window.parent.ifDoneChild(); 
            }
     });