base.options = $.extend({}, $.layer.defaults, options);
base.$layerBox = $(base.options.template);
base.posX = base.posY = 0;
base.moveing = false;

//加载样式
if (!$.layer.hasCss && base.options.cssurl != "") {
$("head", base.options.target).append("");
$.layer.hasCss = true;
}

//加载层对象
$.layer.maskLayerIndex += 20; //调高层位置
base.$layerBox.appendTo("body", base.options.target).css({ "z-index": $.layer.maskLayerIndex }).hide();
base.$layerBox.find("div[class='layer-title']").append(base.options.title);
//判断内容是字符串还是Jquery对象
if (typeof (base.options.content) == "object") {
base.$tempContentParent = base.options.content.parent();
base.tagHide = base.options.content.is(":hidden");
base.$tempContent = base.options.content.clone();
base.options.content.appendTo(base.$layerBox.find("div[class='layer-content']")).show();
}
else {
base.$layerBox.find("div[class='layer-content']").append(base.options.content);
}
//绑定关闭按钮事件
base.$layerBox.find("span[class='layer-close']").mousedown(function(event) {
//阻止事件冒泡
if (event && event.stopPropagation) {
event.stopPropagation();
} else {
window.event.cancelBubble = true;
}
base.close();
return false;
});
base.$layerBox.find("div[class='layer-bar']").mousedown(function(event) {
base.moveStart(event);
});
//base.$layerBox.show();

}

//打开层
base.open = function() {
//层显示动画
//alert($("html", base.options.target).height());
var mtop = ($("html", base.options.target).height() - base.options.height) / 2 + $(document, base.options.target).scrollTop(); //
var mleft = $("html", base.options.target).width() / 2 - base.options.width / 2; //
base.$layerBox.css({ top: base.$el.offset().top, left: base.$el.offset().left, width: 0, height: 0 }).animate({
left: mleft,
top: mtop,
width: base.options.width,
height: base.options.height,
opacity: "show"
}, "slow", function() {
//加载遮罩层
if (base.options.masklayer.show) {
$.layer.maskLayerIndex -= 10; //降低层位置
base.$masklayer = $("");
base.$masklayer.appendTo("body", base.options.target).animate({
opacity: 'toggle'
}, 500);
}
});
}

//开始移动
base.moveStart = function(event) {
base.moveing = true;
base.bgColor = base.$layerBox.css("background-color");
base.$layerBox.css("background-color", "Transparent").children().hide();

base.posX = event.pageX - base.$layerBox.offset().left;
base.posY = event.pageY - base.$layerBox.offset().top; ;
$(document).mousemove(function(event) {
base.moveOn(event);
}).mouseup(function() {
base.moveStop();
});
if ($.browser.msie) {
base.$layerBox.get(0).setCapture();
} else {
document.addEventListener("mousemove", base.moveOn, true);
}
}

//移动中
base.moveOn = function(event) {
if (base.moveing) {
window.getSelection && window.getSelection().removeAllRanges();
base.$layerBox.css({ top: Math.max(event.pageY - base.posY, 0), left: Math.max(event.pageX - base.posX, 0) });
return false;
}
}

//移动停止
base.moveStop = function() {
base.$layerBox.css("background-color", base.bgColor).children().show();
base.moveing = false;
$(document, base.options.target).unbind("mousemove");
if ($.browser.msie) {
base.$layerBox.get(0).releaseCapture();
} else {
document.removeEventListener("mousemove", base.moveOn, true);
}
}

//关闭层
base.close = function() {
if (base.$tempContent) {
base.$tempContent.appendTo(base.$tempContentParent);
if(base.tagHide){
base.$tempContent.hide();
}
}
if (base.options.masklayer.show) {
base.$masklayer.animate({
opacity: 'toggle'
}, 500, function() {
$(this).remove();
base.$layerBox.animate({
left: base.$el.offset().left,
top: base.$el.offset().top,
width: 0,
height: 0,
opacity: "hide"
}, "hide", function() {
$(this).remove();
});
});
}
else {
base.$layerBox.animate({
left: base.$el.offset().left,
top: base.$el.offset().top,
width: 0,
height: 0,
opacity: "hide"
}, "hide", function() {
$(this).remove();
});
}
}

base.init();
}

$.layer.hasCss = false;
$.layer.maskLayerIndex = 1000;
//默认配置
$.layer.defaults = {
masklayer: { show: true, bgcolor: '#eee', alpha: 50 }, //是否显示覆盖层
target: window.self.document,
cssurl: "layer.css",
title: "层标题",
content: "层内容",
width: 500,
height: 300,
template: "×"
}

$.fn.layer = function(options) {
return new $.layer(this, options);
}
})(jQuery);

插件下载地址：jquery.layer.js