js动态生成Html元素实现Post操作（createElement）

<form id="postform" name="postform" method="post">
<input name="msg" value=""/>
</form>

//  theForm.action = "http://msg.baihe.com/tortoise/pages/tortoise/sm_gb2312.jsp"+strReturnURL;
//  document.getElementById("Pathid").value="3070";
//  document.getElementById("Title").value="你好！";
//  document.getElementById("Content").value="我把你设为重点关注了，咱们聊聊吧：）";
//  document.getElementById("CloseWindow").value="1";

var form_feedback = document.createElement("form");
  document.body.appendChild(form_feedback);
    
  var i = document.createElement("input");
  i.type = "hidden";
  i.name = "Title";
  i.value = "你好！";
  form_feedback.appendChild(i);
  
  
  var j=document.createElement("input");
  j.type="hidden";
  j.name="Content";
  j.value="我把你设为重点关注了，咱们聊聊吧：）";
  form_feedback.appendChild(j);
  
  var hiddenIframe=document.createElement("iframe");
  hiddenIframe.src="/UploadFiles/2021-04-02/about:blank">