function image_devis() {
if (document.all)
var xMax = screen.width, yMax = screen.height;
else
if (document.layers)
var xMax = window.outerWidth, yMax = window.outerHeight;
else
var xMax = 1024, yMax=768;
var xOffset = (xMax - 800)/2, yOffset = (yMax - 600)/2;
window.open('devis_abeille_royale.php','Devis',
'width=800,height=500,scrollbars=yes, resizable= yes, toolbar=yes, screenX='+xOffset+',screenY='+yOffset+',top='+yOffset+',left='+xOffset+'');
}