Probleme avec Int et Real

I try to zoom my Webbrowser with the same Factor of the Form scale :

I can zomm webbrowser like these:

 
WebBrowser1.OleObject.Document.Body.Style.Zoom :=2;// or
WebBrowser1.OleObject.Document.Body.Style.Zoom :='200%';

But I would like to calculate the Factor like this :

 
var
zoom : Real;
creenwidth : Integer;
begin
creenwidth := Screen.MonitorFromWindow(Handle).Width;
zoom:= creenwidth div Form1.width;
WebBrowser1.OleObject.Document.Body.Style.Zoom :=zoom; // sa marche pas !