I am using this code to create a small window after clicking on a hyper link, but there is error.
error: the new small window opens but the back big window goes one step back;

I have spent alot of my time to find the solution but in vain.
kindly inform me if any one know.
Thank you.
COde:
<? if(file_exists("images/p1/".$update_id.".jpg")){$path="images/p1/".$update_id.".jpg";?><a href=" " onClick="return popupp('photo.php?path=<?=$path;?>');">Picture 1:</a><? }else print("Picture 1:");?>
///////////////////////java script//////////////////////////
<script language="javascript">
function popupp(url)
{
popUpWindowPicture(url,"Athar",400,600);
}
</script>
<script language="javascript">
function popUpWindowPicture(uri,winname,winheight,winwidth) {
    if (document.all){
        var xMax = screen.width, yMax = screen.height;
    }
    else{
        if (document.layers){
            var xMax = window.outerWidth, yMax = window.outerHeight;
        }
        else{
            var xMax = 800, yMax=600;
    }
    }
    if (xMax<=800){
        var xAdd=0,ySub=0;
        var xOffset = 0, yOffset = (yMax-ySub)/6;
    }
    else{
        var xAdd=0,ySub=0;
        var xOffset = 0, yOffset = (yMax-ySub)/3;
    }
    mywin=window.open(uri,winname,'height='+winheight+ ',width='+winwidth+',screenX='+xOffset+',screenY=' +yOffset+',top='+yOffset+',left='+xOffset+',locati on=0,menubar=0,statusbar=0,locationbar=0,scrollbar s=1,resizable=1');
    mywin.focus();
}
</script>