js实用代码

 1、文本区域变化

<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN"
"http://www.w3.org/TR/html4/loose.dtd">

<html>
<head>
<title>无标题文档</title>
<meta http-equiv="Content-Type" content="text/html; charset=gb2312">
</head>

<body>
<textarea name="word" style="width:400px;height:200px;"></textarea>
<br>
<script language="JavaScript">
<!--
function addField(fieldName)
{
 var myHeight=fieldName.style.height;
 myHeight=myHeight.substr(0,myHeight.indexOf("px")); 
 fieldName.style.height=eval(myHeight)+200;
}
function cutField(fieldName)
{
 var myHeight=fieldName.style.height;
 myHeight=myHeight.substr(0,myHeight.indexOf("px")); 
 if(eval(myHeight)>200){
  fieldName.style.height=eval(myHeight)-200;
 }
}
//-->
</script>
<input type="button" name="Submit" value="增加" onClick="addField(word);">
<input type="button" name="Submit2" value="减少" onClick="cutField(word);">
</body>
</html>

 

2、增加文件

<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN"
"http://www.w3.org/TR/html4/loose.dtd">
<html>
<head>
<title>Untitled Document</title>
<meta http-equiv="Content-Type" content="text/html; charset=gb2312">
<script language="JavaScript">
<!--
function addInputFile(spanId,fileId)
{
   var span = document.getElementById(spanId);
   if ( span !=null ) { 
                 if (navigator.userAgent.indexOf("MSIE") == -1){
      var fileObj = document.createElement("input");
      if ( fileObj != null ) {
       fileObj.type="file";
       fileObj.name = fileId;
       fileObj.id = fileId;
       fileObj.size="50";       
       span.appendChild(fileObj);
      }//if fileObj
      fileObj = document.createElement("br");
      if ( fileObj != null ) {       
       span.appendChild(fileObj);
      }
     }
     else{
      var fileTag = "<input type='file' id ='" + fileId + "' name='" + fileId + "' size=50>";
      var fileObj = document.createElement(fileTag);
      span.appendChild(fileObj);
      fileTag="<br>";
      fileObj = document.createElement(fileTag);
      span.appendChild(fileObj);
     }
   
   }//if span
}

//-->
</script>
</head>

<body>
<form name="form1" method="post" action="">
  <input type="button" name="Button" value="增加文件" onClick="addInputFile('fileName','baobao');">
  <br>
  <span id="fileName"></span>
</form>
</body>
</html>
3、增加文本

<script>
function delOption(e){
e.previousSibling.value="";
e.previousSibling.removeNode();
e.nextSibling.removeNode();
e.removeNode();
}

function addOption(name){
var newTextArea = document.createElement('<textarea name="qOption"></textarea>')
var newButton = document.createElement('<input type="button" onclick="delOption(this)" value=" 删  除 ">');
var newBr = document.createElement('<br>')
var parentNode=document.all[name];
parentNode.appendChild(newTextArea);
parentNode.appendChild(newButton);
parentNode.appendChild(newBr);
}
</script>
<input type="button" onclick="addOption('option')" value=" 增  加 "><br>
<span id="option" ></span>

 

 

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