使用window.onload = function(){}仍然无法解决“按钮”
程序代码：<!DOCTYPE HTML >
<HTML>
<HEAD>
<TITLE> 实验一下 </TITLE>
</HEAD>
<BODY>
<H2>员工信息列表</H2>
<input type = "button" value = "显示员工信息列表" id = "displayBtn "/>
<hr>
<table border = 1px width = "50%">
<tr>
<th>员工编号</th>
<th>员工名字</th>
<th>员工薪资</th>
</tr>
<TBODY id = "emptbody">
<!--
<tr>
<td>7369</td>
<td>SMITH</td>
<td>800</td>
</tr>
<tr>
<td>7369</td>
<td>SMITH</td>
<td>800</td>
</tr>
<tr>
<td>7369</td>
<td>SMITH</td>
<td>800</td>
</tr>
-->
</TBODY>
</table>
总共<span id = "count">0</span>条数
<script type = "text/javascript">
//有这些json数据
var data = {
"total" :4,
"emps" : [
{"empno" : 7369, "ename" : "SMITH" , "sal":800.0},
{"empno" : 7361, "ename" : "SMITH2" , "sal":1800.0},
{"empno" : 7362, "ename" : "SMITH3" , "sal":2808.0},
{"empno" : 7363, "ename" : "SMITH4" , "sal":3800.0}
]
}
//希望把数据展示到table中
window.onload = function(){
//alert(11);
document.getElementById("displayBtn").onclick = function(){
var emps = data.emps;
var html = "";
for(var i = 0; i <emps.length; i++){
var emp = emps[i];
html += "<tr>";
html += "<td>"+emp.empno+"</td>";
html += "<td>"+emp.ename+"</td>";
html += "<td>"+emp.sal+"</td>";
html += "</tr>";
}
document.getElementById("emptbody").innerHTML = html;
document.getElementById("count").innerHTML = data.total;
}
}
</script>
</BODY>
</HTML>
按下按钮“显示员工信息列表”却不能将详细信息显示出来，控制台显示“Uncaught TypeError: Cannot set property 'onclick' of null
at window.onload”，我有使用window.onload啊，也有将onclick放到下面来。
