var stop = 0;
var padding = 30;
var X = 0;
var Y = 50;
var popup = 'promocao';
var tamanho = 380;

function slideMyPopup() {
 X-=25;
 if( X < stop ) return;
 document.getElementById(popup).style.left = X + "px";
 setTimeout("slideMyPopup()", 25);
}

function fireMyPopup(meuPopup, tamanhoParam) {
 popup = meuPopup;
 tamanho = tamanhoParam;
 var scrolledX;
 if( self.pageYOffset ) {
   scrolledX = self.pageXOffset;
 } else if( document.documentElement && document.documentElement.scrollTop ) {
   scrolledX = document.documentElement.scrollLeft;
 } else if( document.body ) {
   scrolledX = document.body.scrollLeft;
 }

 var centerX;
 if( self.innerHeight ) {
   centerX = self.innerWidth;
 } else if( document.documentElement && document.documentElement.clientHeight ) {
   centerX = document.documentElement.clientWidth;
 } else if( document.body ) {
   centerX = document.body.clientWidth;
 }

 // Don't forget to subtract popup's width! ( 380 in our case )

 stop = scrolledX + centerX - tamanho - padding;
 X = scrolledX + centerX;

 document.getElementById(popup).style.top = Y + "px";
 document.getElementById(popup).style.display = "block";
 slideMyPopup();
}

function styledPopupClose() {
 document.getElementById(popup).style.display = "none";
 Y = bottom; // if it was closed, make sure extra computations are done in dropMyPopup()
}