js method to implement a simple message board using DOM operations-JS Tutorial-php.cn

js method to implement a simple message board using DOM operations

高洛峰

Release： 2017-02-06 09:41:07

Original

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The example of this article describes the method of using js to implement a simple message board using DOM operations. Share it with everyone for your reference. The specific analysis is as follows:

The simple message board shown in the picture is a self-entertainment version. To put it bluntly, it is to practice DOM operations.

js method to implement a simple message board using DOM operations

Point one: document.createElement("tag name") New element

Point two: Parent element.appendChild("element") Add the new element The element is inserted into the tag of the page (displayed at the last tag), so that it will be displayed in the browser

Point 3: Parent element.insertBefore("Element","Before which element to insert ") Insert the newly created element in front of the specified tag on the page, so that the content entered later will be displayed in front

Point 4: Parent element.removeChild("Element") Delete the specified element

Below, the code:

<!DOCTYPE html>
<html>
<head>
<meta charset="utf-8" />
<title>无标题文档</title>
<script>
window.onload = function(){
 var oMsg = document.getElementById("msg");
 var oBtn = document.getElementById("btn");
 var oMsg_c = document.getElementById("msg_c");
 var oUl = document.createElement("ul");
 oMsg_c.appendChild(oUl);
 oBtn.onclick = function(){
  var sVal = oMsg.value;
  var oli = document.createElement("li");
  oli.innerHTML = sVal + " <span>删除</span>";
  var oli1 = oUl.getElementsByTagName("li");
  if(oli1.length>0){
   oUl.insertBefore(oli,oli1[0]);
  }else{
   oUl.appendChild(oli);
  }
  oMsg.value=&#39;&#39;;
   var oSpan = document.getElementsByTagName("span");
   for(var i=0; i<oSpan.length; i++){
    oSpan[i].onclick = function(){
     oUl.removeChild(this.parentNode);
    }
   }
 }
} 
</script>
</head>
<body>
<h1>简易留言板</h1>
<input id="msg" type="text" size="40" value="">
<input id="btn" type="button" value="留言">
<div id="msg_c"></div>
</body>
</html>

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I hope this article will be helpful to everyone’s JavaScript programming design.

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