ExtJs:el与contentEl区别

1、把<div id="div_exam"></div>嵌入到当前Ext元素panel内:

{
     fieldLabel: "上传图片",
          xtype: 'panel',
     contentEl: 'div_exam'
}

 
效果:

<div class="x-panel-body x-panel-body-noheader" id="ext-gen155" style="width: 500px;">
      <div id="div_exam"></div>
</div>

 

2、.把当前Ext元素panel嵌入到<div id="div_exam"></div>内

 {
       fieldLabel: "上传图片",
               width: 200,
               xtype: 'panel',
                     el: 'div_exam'
}

 
效果:

<div id="div_exam">
      <div class="x-panel-body x-panel-body-noheader" id="ext-gen155" style="width: 500px;">....</div>
</div>