<script>
function showcontent(){
var str="这里面是阅读的内容";
if(document.getElementById("td1").innerHTML==""){
document.getElementById("td1").innerHTML=str;
}
else{
document.getElementById("td1").innerHTML=""
}
}
</script><table>
<tr>
<td id="td1">
</td>
</tr>
<caption> <input type="button" value="点击阅读" onclick="showcontent()"> </caption>
</table>
function showcontent(){
var str="这里面是阅读的内容";
if(document.getElementById("td1").innerHTML==""){
document.getElementById("td1").innerHTML=str;
}
else{
document.getElementById("td1").innerHTML=""
}
}
</script><table>
<tr>
<td id="td1">
</td>
</tr>
<caption> <input type="button" value="点击阅读" onclick="showcontent()"> </caption>
</table>
xxx=div
xx.innerHTML