打开窗口

function (btn) {
        var cloneDom = $("<div  class='allPopModal'><div class='allModalZhezhao'></div></div>");
        cloneDom.append($(btn))
        $("body").append(cloneDom)
        $(btn).css("margin", "0 auto")
        $(btn).show()
        var left = ($("body")[0].offsetWidth - $(btn)[0].offsetWidth) / 2;
        var marginTop = ($("body")[0].offsetHeight - $(btn)[0].offsetHeight) / 2;
        $(btn).css("margin-top", marginTop + "px")
        $(btn).css("left", left + "px")