diff --git a/docs/form/checkbox.md b/docs/form/checkbox.md
index 7946487c..774add63 100644
--- a/docs/form/checkbox.md
+++ b/docs/form/checkbox.md
@@ -18,7 +18,20 @@ toc: true
   <input type="checkbox" name="AAA" title="默认">
   <input type="checkbox" name="BBB" lay-text="选中" checked> 
   <input type="checkbox" name="CCC" title="禁用" disabled> 
+  <input type="checkbox" name="DDD" title="半选" id="ID-checkbox-ind"> 
 </div>
+
+<!-- import layui -->
+<script>
+layui.use(function(){
+  var form = layui.form;
+  var $ = layui.$;
+
+  // 初始设置半选
+  $('#ID-checkbox-ind').prop('indeterminate', true); // 半选属性只能动态设置
+  form.render('checkbox');
+});
+</script>
   </textarea>
 </pre>
 
@@ -41,7 +54,7 @@ toc: true
 <div class="layui-form">
   <input type="checkbox" name="AAA" title="默认" lay-skin="tag">
   <input type="checkbox" name="BBB" title="选中" lay-skin="tag" checked> 
-  <input type="checkbox" name="CCC" title="禁用" lay-skin="tag" disabled> 
+  <input type="checkbox" name="CCC" title="禁用" lay-skin="tag" disabled>
 </div>
 
 <!-- import layui -->
diff --git a/docs/layer/detail/demo.md b/docs/layer/detail/demo.md
index 633993a6..8aa37919 100644
--- a/docs/layer/detail/demo.md
+++ b/docs/layer/detail/demo.md
@@ -16,6 +16,8 @@
 
 <h3 id="demo-alert" lay-toc="{level: 3}">信息框</h3>
 
+信息框即 `dialog` 类型层，对应默认的 `type: 0`，该类型的弹层同时只能存在一个。更多说明详见：[#type](#options)
+
 <pre class="layui-code" lay-options="{preview: true, codeStyle: 'height: 535px;', layout: ['preview', 'code'], tools: ['full']}">
   <textarea>
 {{- d.include("/layer/examples/alert.md") }}
diff --git a/docs/layer/detail/options.md b/docs/layer/detail/options.md
index 4c65de25..415169b8 100644
--- a/docs/layer/detail/options.md
+++ b/docs/layer/detail/options.md
@@ -20,11 +20,11 @@
   
 弹层类型。 可选值有：
 
-- `0` dialog 信息框
-- `1` page 页面层
-- `2` iframe 内联框架层
-- `3` loading 加载层
-- `4` tips 贴士层
+- `0` dialog 信息框（默认），*同时只能存在一个层*
+- `1` page 页面层，*可同时存在多个层*
+- `2` iframe 内联框架层，*可同时存在多个层*
+- `3` loading 加载层，*同时只能存在一个层*
+- `4` tips 贴士层，*可配置同时存在多个层*
 
 `layer` 弹层由以上 5 种类型构成。 不同的类型代表不同的弹出形态，`layer` 提供的所有的弹出方式均由此衍生。
 
diff --git a/src/css/layui.css b/src/css/layui.css
index c14ae851..cf131409 100644
--- a/src/css/layui.css
+++ b/src/css/layui.css
@@ -821,7 +821,7 @@ a cite{font-style: normal; *cursor:pointer;}
 .layui-form-checkbox{position: relative; display: inline-block; vertical-align: middle; height: 30px; line-height: 30px; margin-right: 10px; padding-right: 30px; background-color: #fff; cursor: pointer; font-size: 0;  -webkit-transition: .1s linear; transition: .1s linear; box-sizing: border-box;}
 .layui-form-checkbox:hover{}
 .layui-form-checkbox > *{display: inline-block; vertical-align: middle;}
-.layui-form-checkbox > div{padding: 0 11px; height: 100%; font-size: 14px; border-radius: 2px 0 0 2px; background-color: #d2d2d2; color: #fff; overflow: hidden; white-space: nowrap; text-overflow: ellipsis;}
+.layui-form-checkbox > div{padding: 0 11px; font-size: 14px; border-radius: 2px 0 0 2px; background-color: #d2d2d2; color: #fff; overflow: hidden; white-space: nowrap; text-overflow: ellipsis;}
 .layui-form-checkbox:hover > div{background-color: #c2c2c2;}
 .layui-form-checkbox > i{position: absolute; right: 0; top: 0; width: 30px; height: 100%; border: 1px solid #d2d2d2; border-left: none; border-radius: 0 2px 2px 0; color: #fff; color: rgba(255,255,255,0); font-size: 20px; text-align: center; box-sizing: border-box;}
 .layui-form-checkbox:hover > i{border-color: #c2c2c2; color: #c2c2c2;}
@@ -838,7 +838,7 @@ a cite{font-style: normal; *cursor:pointer;}
 /* 复选框-默认风格 */
 .layui-form-checkbox[lay-skin="primary"]{height: auto!important; line-height: normal!important; min-width: 18px; min-height: 18px; border: none!important; margin-right: 0; padding-left: 24px; padding-right: 0; background: none;}
 .layui-form-checkbox[lay-skin="primary"] > div{margin-top: -1px; padding-left: 0; padding-right: 15px; line-height: 18px; background: none; color: #5F5F5F;}
-.layui-form-checkbox[lay-skin="primary"] > i{right: auto; left: 0; width: 18px; height: 18px; line-height: 16px; border: 1px solid #d2d2d2; font-size: 12px; border-radius: 2px; background-color: #fff; -webkit-transition: .1s linear; transition: .1s linear;}
+.layui-form-checkbox[lay-skin="primary"] > i{right: auto; left: 0; width: 16px; height: 16px; line-height: 14px; border: 1px solid #d2d2d2; font-size: 12px; border-radius: 2px; background-color: #fff; -webkit-transition: .1s linear; transition: .1s linear;}
 .layui-form-checkbox[lay-skin="primary"]:hover > i{border-color: #16b777; color: #fff;}
 .layui-form-checked[lay-skin="primary"] > i{border-color: #16b777 !important; background-color: #16b777; color: #fff;}
 .layui-checkbox-disabled[lay-skin="primary"] > div{background: none!important;}
@@ -1014,7 +1014,7 @@ a cite{font-style: normal; *cursor:pointer;}
 .layui-table-view .layui-table td[data-edit]{cursor: text;}
 .layui-table-view .layui-table td[data-edit]:hover:after{position: absolute; left: 0; top: 0; width: 100%; height: 100%; box-sizing: border-box; border: 1px solid #16B777; pointer-events: none; content: "";}
 
-.layui-table-view .layui-form-checkbox[lay-skin="primary"] i{width: 18px; height: 18px;}
+.layui-table-view .layui-form-checkbox[lay-skin="primary"] i{width: 18px; height: 18px; line-height: 16px;}
 .layui-table-view .layui-form-radio{line-height: 0; padding: 0;}
 .layui-table-view .layui-form-radio>i{margin: 0; font-size: 20px;}
 .layui-table-init{position: absolute; left: 0; top: 0; width: 100%; height: 100%; text-align: center; z-index: 199;}
diff --git a/src/css/modules/layer.css b/src/css/modules/layer.css
index f043c6ee..5b45dd7a 100644
--- a/src/css/modules/layer.css
+++ b/src/css/modules/layer.css
@@ -191,7 +191,7 @@ html #layuicss-layer{display: none; position: absolute; width: 1989px;}
 
 /* 内置 skin */
 .layui-layer-lan .layui-layer-title{background:#4476A7; color:#fff; border: none;}
-.layui-layer-lan .layui-layer-btn{padding: 5px 10px 10px; text-align: right; border-top:1px solid #E9E7E7}
+.layui-layer-lan .layui-layer-btn{padding: 5px 10px 10px; border-top:1px solid #E9E7E7}
 .layui-layer-lan .layui-layer-btn a{background: #fff; border-color: #E9E7E7; color: #333;}
 .layui-layer-lan .layui-layer-btn .layui-layer-btn1{background:#C9C5C5;}
 .layui-layer-molv .layui-layer-title{background: #009f95; color:#fff; border: none;}
diff --git a/src/modules/code.js b/src/modules/code.js
index 3db86394..aa6c4ba6 100644
--- a/src/modules/code.js
+++ b/src/modules/code.js
@@ -186,8 +186,15 @@ layui.define(['lay', 'util', 'element', 'form'], function(exports){
         });
 
         // copy
-        if(options.copy && layui.type(options.tools) === 'array'){
-          options.tools.unshift('copy');
+        if(options.copy){
+          if(layui.type(options.tools) === 'array'){
+            // 若 copy 未存在于 tools 中，则追加到最前
+            if(options.tools.indexOf('copy') === -1){
+              options.tools.unshift('copy');
+            }
+          } else {
+            options.tools = ['copy'];
+          }
         }
 
         // 工具栏事件
@@ -217,7 +224,7 @@ layui.define(['lay', 'util', 'element', 'form'], function(exports){
         
         // 追加预览
         if(isIframePreview){
-          elemPreviewView.html('<iframe></iframe>');
+          elemPreviewView.html('<iframe allowtransparency="true" frameborder="0"></iframe>');
         }
 
         // 执行预览
diff --git a/src/modules/form.js b/src/modules/form.js
index d11ee935..4cda8b4f 100644
--- a/src/modules/form.js
+++ b/src/modules/form.js
@@ -690,12 +690,12 @@ layui.define(['lay', 'layer', 'util'], function(exports){
           }()));
           var disabled = this.disabled;
 
-          if(!skins[skin]) skin = 'primary'; // 若非内置风格，则强制为默认风格
+          // if(!skins[skin]) skin = 'primary'; // 若非内置风格，则强制为默认风格
           var RE_CLASS = CLASS[skin] || CLASS.checkbox;
 
           // 替代元素
           var hasRender = othis.next('.' + RE_CLASS[0]);
-          hasRender[0] && hasRender.remove(); // 如果已经渲染，则Rerender
+          hasRender[0] && hasRender.remove(); // 若已经渲染，则 Rerender
          
           // 若存在标题模板，则优先读取标题模板
           if(othis.next('[lay-checkbox]')[0]){