Javascript 动态添加&删除列表框内容
Body部份：
<div>
<table width="613" border="0" cellpadding="2" cellspacing="1" id="SignFrame">
<tr id="trHeader">
<td width="27" bgcolor="#96E0E2">序号</td>
<td width="64" bgcolor="#96E0E2">用户姓名</td>
<td width="98" bgcolor="#96E0E2">电子邮箱</td>
<td width="92" bgcolor="#96E0E2">固定电话</td>
<td width="86" bgcolor="#96E0E2">移动手机</td>
<td width="153" bgcolor="#96E0E2">公司名称</td>
<td width="57" align="center" bgcolor="#96E0E2">&nbsp;</td>
</tr>
</table>
</div>
<div>
<input type="button" name="Submit" value="添加参与人" onclick="AddSignRow()" />
<input type="button" name="Submit2" value="清空" onclick="ClearAllSign()" />
<input name='txtTRLastIndex' type='hidden' id='txtTRLastIndex' value="1" />
</div>

JS代码部份
<script language="javascript">// Example: obj = findObj("image1");
function findObj(theObj, theDoc){ var p, i, foundObj; if(!theDoc) theDoc = document; if( (p = theObj.indexOf("?")) > 0 && parent.frames.length) { theDoc = parent.frames[theObj.substring(p+1)].document; theObj = theObj.substring(0,p); } if(!(foundObj = theDoc[theObj]) && theDoc.all) foundObj = theDoc.all[theObj]; for (i=0; !foundObj && i < theDoc.forms.length; i++) foundObj = theDoc.forms[i][theObj]; for(i=0; !foundObj && theDoc.layers && i < theDoc.layers.length; i++) foundObj = findObj(theObj,theDoc.layers[i].document); if(!foundObj && document.getElementById) foundObj = document.getElementById(theObj); return foundObj;}
//添加一个参与人填写行
function AddSignRow(){//读取最后一行的行号，存放在txtTRLastIndex文本框中
var txtTRLastIndex = findObj("txtTRLastIndex",document);
var rowID = parseInt(txtTRLastIndex.value);

var signFrame = findObj("SignFrame",document);
//添加行
var newTR = signFrame.insertRow(signFrame.rows.length);
newTR.id = "SignItem" + rowID;

//添加列:序号
var newNameTD=newTR.insertCell(0);
//添加列内容
newNameTD.innerHTML = newTR.rowIndex.toString();

//添加列:姓名
var newNameTD=newTR.insertCell(1);
//添加列内容
newNameTD.innerHTML = "<input name='txtName" + rowID + "' id='txtName" + rowID + "' type='text' size='12' />";

//添加列:电子邮箱
var newEmailTD=newTR.insertCell(2);
//添加列内容
newEmailTD.innerHTML = "<input name='txtEMail" + rowID + "' id='txtEmail" + rowID + "' type='text' size='20' />";

//添加列:电话
var newTelTD=newTR.insertCell(3);
//添加列内容
newTelTD.innerHTML = "<input name='txtTel" + rowID + "' id='txtTel" + rowID + "' type='text' size='10' />";

//添加列:手机
var newMobileTD=newTR.insertCell(4);
//添加列内容
newMobileTD.innerHTML = "<input name='txtMobile" + rowID + "' id='txtMobile" + rowID + "' type='text' size='12' />";

//添加列:公司名
var newCompanyTD=newTR.insertCell(5);
//添加列内容
newCompanyTD.innerHTML = "<input name='txtCompany" + rowID + "' id='txtCompany" + rowID + "' type='text' size='20' />";


//添加列:删除按钮
var newDeleteTD=newTR.insertCell(6);
//添加列内容
newDeleteTD.innerHTML = "<div align='center' style='width:40px'><a href='javascript:;' onclick=\"DeleteSignRow('SignItem" + rowID + "')\">删除</a></div>";

//将行号推进下一行
txtTRLastIndex.value = (rowID + 1).toString() ;
}
//删除指定行
function DeleteSignRow(rowid){
var signFrame = findObj("SignFrame",document);
var signItem = findObj(rowid,document);

//获取将要删除的行的Index
var rowIndex = signItem.rowIndex;

//删除指定Index的行
signFrame.deleteRow(rowIndex);

//重新排列序号，如果没有序号，这一步省略
for(i=rowIndex;i<signFrame.rows