Check if window has focus

Question

Why not use the hasFocus method e.g.

if (document.hasFocus()) {
    ...
}

---

If you need to handle iframe's as well then your check just becomes either or e.g.

function isFocused() {
    return document.hasFocus() || document.getElementById('iframe').contentWindow.document.hasFocus();
}

You can use document.visibilityState to know whether the page is in focus or not.

var has_focus = true;

function loading_time() {
    $(":focus").each(function() {
      if($(this).attr("id")=="iframeID") has_focus = true;
    });

    if(has_focus==true) alert('page has focus');
    else alert('page has not focus');

    setTimeout("loading_time()", 2000);
}

window.onblur = function(){  
    has_focus=false;  
}  
window.onfocus = function(){  
    has_focus=true;  
}

$(window).load(function(){
    setTimeout("loading_time()", 2000);
});

To make it more efficient, you need to var has_focus = false; and make the user click somewhere on the page.

Cross Browser jQuery Solution! The following plugin will go through your standard test for various versions of IE, Chrome, Firefox, Safari, etc.. and establish your declared methods accordingly. It also deals with issues such as:

• timers! ewwww!
• onblur|.blur/onfocus|.focus "duplicate" calls
• window losing focus through selection of alternate app, like word
• • This tends to be undesirable simply because, if you have a bank page open, and it's onblur event tells it to mask the page, then if you open calculator, you can't see the page anymore!
• Not triggering on page load

Use is as simple as:

$.winFocus(function(event, isVisible) {
    console.log("Combo\t\t", event, isVisible);
});

//  OR Pass False boolean, and it will not trigger on load,
//  Instead, it will first trigger on first blur of current tab_window
$.winFocus(function(event, isVisible) {
    console.log("Combo\t\t", event, isVisible);
}, false);

//  OR Establish an object having methods "blur" & "focus", and/or "blurFocus"
//  (yes, you can set all 3, tho blurFocus is the only one with an 'isVisible' param)
$.winFocus({
    blur: function(event) {
        console.log("Blur\t\t", event);
    },
    focus: function(event) {
        console.log("Focus\t\t", event);
    }
});

//  OR First method becoms a "blur", second method becoms "focus"!
$.winFocus(function(event) {
    console.log("Blur\t\t", event);
},
function(event) {
    console.log("Focus\t\t", event);
});

---

New&improvedversion,madeforbothvanillaandjQueryfoundhere!

---

/*    Begin Plugin    */
;;(function($){$.winFocus||($.extend({winFocus:function(){var a=!0,b=[];$(document).data("winFocus")||$(document).data("winFocus",$.winFocus.init());for(x in arguments)"object"==typeof arguments[x]?(arguments[x].blur&&$.winFocus.methods.blur.push(arguments[x].blur),arguments[x].focus&&$.winFocus.methods.focus.push(arguments[x].focus),arguments[x].blurFocus&&$.winFocus.methods.blurFocus.push(arguments[x].blurFocus),arguments[x].initRun&&(a=arguments[x].initRun)):"function"==typeof arguments[x]?b.push(arguments[x]):
"boolean"==typeof arguments[x]&&(a=arguments[x]);b&&(1==b.length?$.winFocus.methods.blurFocus.push(b[0]):($.winFocus.methods.blur.push(b[0]),$.winFocus.methods.focus.push(b[1])));if(a)$.winFocus.methods.onChange()}}),$.winFocus.init=function(){$.winFocus.props.hidden in document?document.addEventListener("visibilitychange",$.winFocus.methods.onChange):($.winFocus.props.hidden="mozHidden")in document?document.addEventListener("mozvisibilitychange",$.winFocus.methods.onChange):($.winFocus.props.hidden=
"webkitHidden")in document?document.addEventListener("webkitvisibilitychange",$.winFocus.methods.onChange):($.winFocus.props.hidden="msHidden")in document?document.addEventListener("msvisibilitychange",$.winFocus.methods.onChange):($.winFocus.props.hidden="onfocusin")in document?document.onfocusin=document.onfocusout=$.winFocus.methods.onChange:window.onpageshow=window.onpagehide=window.onfocus=window.onblur=$.winFocus.methods.onChange;return $.winFocus},$.winFocus.methods={blurFocus:[],blur:[],focus:[],
exeCB:function(a){$.winFocus.methods.blurFocus&&$.each($.winFocus.methods.blurFocus,function(b,c){this.apply($.winFocus,[a,!a.hidden])});a.hidden&&$.winFocus.methods.blur&&$.each($.winFocus.methods.blur,function(b,c){this.apply($.winFocus,[a])});!a.hidden&&$.winFocus.methods.focus&&$.each($.winFocus.methods.focus,function(b,c){this.apply($.winFocus,[a])})},onChange:function(a){var b={focus:!1,focusin:!1,pageshow:!1,blur:!0,focusout:!0,pagehide:!0};if(a=a||window.event)a.hidden=a.type in b?b[a.type]:
document[$.winFocus.props.hidden],$(window).data("visible",!a.hidden),$.winFocus.methods.exeCB(a);else try{$.winFocus.methods.onChange.call(document,new Event("visibilitychange"))}catch(c){}}},$.winFocus.props={hidden:"hidden"})})(jQuery);
/*    End Plugin      */

// Simple example
$(function() {
	$.winFocus(function(event, isVisible) {
		$('td tbody').empty();
		$.each(event, function(i) {
			$('td tbody').append(
				$('<tr />').append(
					$('<th />', { text: i }),
					$('<td />', { text: this.toString() })
				)
			)
		});
		if (isVisible) 
			$("#isVisible").stop().delay(100).fadeOut('fast', function(e) {
				$('body').addClass('visible');
				$(this).stop().text('TRUE').fadeIn('slow');
			});
		else {
			$('body').removeClass('visible');
			$("#isVisible").text('FALSE');
		}
	});
})

body { background: #AAF; }
table { width: 100%; }
table table { border-collapse: collapse; margin: 0 auto; width: auto; }
tbody > tr > th { text-align: right; }
td { width: 50%; }
th, td { padding: .1em .5em; }
td th, td td { border: 1px solid; }
.visible { background: #FFA; }

<script src="https://ajax.googleapis.com/ajax/libs/jquery/1.9.1/jquery.min.js"></script>
<h3>See Console for Event Object Returned</h3>
<table>
    <tr>
        <th><p>Is Visible?</p></th>
        <td><p id="isVisible">TRUE</p></td>
    </tr>
    <tr>
        <td colspan="2">
            <table>
                <thead>
                    <tr>
                        <th colspan="2">Event Data <span style="font-size: .8em;">{ See Console for More Details }</span></th>
                    </tr>
                </thead>
                <tbody></tbody>
            </table>
        </td>
    </tr>
</table>