دکمه های روشن و خاموش کردن صفحه وب

كد:

<img src="http://rozup.ir/view/1634779/light.png" style="position:fixed;top:10px;right:10px;cursor:pointer;z-index:99999;" onclick="dayAndNight.day();"/>
<img src="http://rozup.ir/view/1634778/dark.png" style="position:fixed;top:10px;right:50px;cursor:pointer;z-index:99999;" onclick="dayAndNight.night(this);"/>
<script type="text/javascript">
x=0;
var dayAndNight={
    night : function(dis){
        x++;
        if(x<2){
        goToSleep=document.createElement('div');
        goToSleep.style.cssText='width:100%;height:100%;position:fixed;background:#000;opacity:.9;top:0px;left:0px;';
        goToSleep.id='webcodesOnAndOff';
        (document.body || document.documentElement).appendChild(goToSleep);
    }
    },
    day : function(){
        var b=document.getElementsByClassName('webcodesOnAndOff');
        document.body.removeChild(document.getElementById('webcodesOnAndOff'));
        x=0;
    }
}
</script>
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