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                        /JavaScript進(jìn)階篇

添加一行這里的判斷為什么不管用？

<!DOCTYPE?html>
<html>
?<head>
??<title>?new?document?</title>??
??<meta?http-equiv="Content-Type"?content="text/html;?charset=gbk"/>???
??<script?type="text/javascript">?
??
????window.onload?=?function(){
????????var?acolor=document.getElementsByTagName("td");
????????for(i=0;i<acolor.length;i++){
???????????????acolor[i].onmouseover=function(){
???????????????this.style.backgroundColor="#D8D8D8";
???????????}
???????????acolor[i].onmouseout=function(){
???????????????this.style.backgroundColor="#fff";
???????????}
????????}
????}???
?????//?鼠標(biāo)移動(dòng)改變背景,可以通過給每行綁定鼠標(biāo)移上事件和鼠標(biāo)移除事件來改變所在行背景色。
???????
????????var?num=3;
????function?add(){
????????var?adda=document.getElementById("table");
????????
????????var?newadda=document.createElement("tr");
????????var?newaddb=document.createElement("td");
????????var?newaddc=document.createElement("td");
????????var?newaddd=document.createElement("td");
????????
????????newaddc.innerHTML=prompt("姓名:");
????????newaddb.innerHTML=num;
????????newaddd.innerHTML="<a?href='javascript:;'?onclick=''>刪除</a>";
????????if(newaddc!=""&&newaddc!=null){
????????adda.appendChild(newadda);
????????newadda.appendChild(newaddb);
????????newadda.appendChild(newaddc);
????????newadda.appendChild(newaddd);
????????}
????????else{
????????????alert("請輸入正確內(nèi)容");
????????}
????????num++;
????}
??????//?編寫一個(gè)函數(shù)，供添加按鈕調(diào)用，動(dòng)態(tài)在表格的最后一行添加子節(jié)點(diǎn)；
?????
????????????????
????????
?????//?創(chuàng)建刪除函數(shù)
?????


??</script>?
?</head>?
?<body>?
???????<table?border="1"?width="50%"?id="table">
???????<tr>
????????<th>學(xué)號</th>
????????<th>姓名</th>
????????<th>操作</th>
???????</tr>??

???????<tr>
????????<td>1</td>
????????<td>王小明</td>
????????<td><a?href="javascript:;"?onclick="removea"?>刪除</a></td>???<!--在刪除按鈕上添加點(diǎn)擊事件??-->
???????</tr>

???????<tr>
????????<td>2</td>
????????<td>劉小芳</td>
????????<td><a?href="javascript:;"?onclick="removea"?>刪除</a></td>???<!--在刪除按鈕上添加點(diǎn)擊事件??-->
???????</tr>??

???????</table>
???????<input?type="button"?value="添加一行"?onclick="add()"?/>???<!--在添加按鈕上添加點(diǎn)擊事件??-->
?</body>
</html>