JS获取ewebeditor的值

< HTML >  
     < HEAD >
     < TITLE > eWebEditor ： 标准调用示例 </ TITLE >  
     < META  http-equiv =Content-Type  content ="text/html; charset=gb2312" >  
     < link  rel ='stylesheet'  type ='text/css'  href ='example.css' >  
     < script >  
    <!--
        function validateForm()
        { 
            //执行iframe页面中的AttachSubmit函数 
            window.frames["eWebEditor1"].AttachSubmit();
            if(document.getElementByIdx_x("content").value != "")
            { 
                alert(document.getElementByIdx_x("content").value);
            }
            else
            { 
                alert("空"); 
            }
        }
    -->
     </ script >  
     </ HEAD >  
     < BODY >  
     < FORM  method ="post"  name ="myform" >  
         < TABLE  border ="0"  cellpadding ="2"  cellspacing ="1" >  
             < TR >  
                 < TD > 编辑内容： </ TD >  
                 < TD >  
                     < INPUT  type ="hidden"  name ="content"   >  
                     < IFRAME  ID ="eWebEditor1"  src ="ewebeditor.htm?id=content&style=coolblue"  frameborder ="0"  scrolling ="no"  width ="550"  height ="350" ></ IFRAME >  
                 </ TD >  
             </ TR >  
             < TR >  
                 < TD  colspan =2  align =right >  
                     < INPUT  type =button  value ="提交"  onclick ="validateForm();" >  
                     < INPUT  type =reset  value ="重填" >  
                     < INPUT  type =button  value ="查看源文件"  onclick ="location.replace('view-source:'+location)" >  
                 </ TD >  
             </ TR >  
         </ TABLE >  
     </ FORM >  
     </ BODY >  
     </ HTML >