function ResizeAndMove(sizeW,sizeH)
{
    var W=sizeW;
    var H=sizeH;
    
    var SW=screen.availWidth;
    var SH=screen.availHeight;
    
    if (W>SW) 
    {
        W=SW
    } 
    if (H>SH) 
    {
        H=SH
    } 
    
    window.resizeTo(W,H);
    
    var X=(SW-W)/2;
    var Y=(SH-H)/2;
    
    window.moveTo(X,Y);
}

var WW = 798;
var WH = 730;

ResizeAndMove(WW,WH)

window.focus();