不明白为什么一定要用this
<!DOCTYPE html>
<html>
<head>
<title> new document </title>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8"/>
<script type="text/javascript">
window.onload = function(){
var trs = document.getElementsByTagName('tr');
for(var i = 1; i < trs.length; i++){
trs[i].onmouseover = function(){
this.style.backgroundColor = "#f2f2f2";
}
//我的想法是var color=trs[i].style.backgroundColor="#f2f2f2";
// trs[i].onmouseover = color;这样是不对的但是不知道为什么
trs[i].onmouseout = function(){
this.style.backgroundColor = "#fff";
}
}
}
</script>
</head>
<body>
<table border="1" width="50%" id="table">
<tr>
<th>学号</th>
<th>姓名</th>
<th>操作</th>
</tr>
<tr>
<td>xh001</td>
<td>王小明</td>
<td><a href="#" onclick = "deleteItem(this);return false;" >删除</a></td>
</tr>
<tr>
<td>xh002</td>
<td>刘小芳</td>
<td><a href="javasript:;" onclick = "deleteItem(this);" >删除</a></td>
</tr>
</table>
<input type="button" value="添加一行" onclick = "addTo();"/>
</body>
</html>
我想改个好听点的名字2回答
-
李晓健
window.onload = function(){ var trs = document.getElementsByTagName('tr'); for(var i = 1; i < trs.length; i++){ // trs[i].onmouseover = function(){ // //你在这里alert一下i 看看是不是你想要的值你就明白了 // this.style.backgroundColor = "#f2f2f2"; // }; //如果非要用trs[i] 可以这样试试 (function(i){ trs[i].onmouseover = function(){ trs[i].style.backgroundColor = "#f2f2f2"; } }(i)) //我的想法是var color=trs[i].style.backgroundColor="#f2f2f2"; // trs[i].onmouseover = color;这样是不对的但是不知道为什么 trs[i].onmouseout = function(){ this.style.backgroundColor = "#fff"; } } }看注释 -
echo_kinchao
this是特指标识
随时随地看视频慕课网APP
相关分类
JavaScript