javascript 无法设置未定义或空引用的属性“innerHTML”
声明：本页面是StackOverFlow热门问题的中英对照翻译，遵循CC BY-SA 4.0协议，如果您需要使用它，必须同样遵循CC BY-SA许可，注明原文地址和作者信息，同时你必须将它归于原作者（不是我）：StackOverFlow
原文地址: http://stackoverflow.com/questions/28522160/
Warning: these are provided under cc-by-sa 4.0 license. You are free to use/share it, But you must attribute it to the original authors (not me):
StackOverFlow
Unable to set property 'innerHTML' of undefined or null reference
提问by Jane wang
Get this strange error. I am learning javaScript and copy the code from somewhere and run it but get the error. Here is the code. Change the empty string to any other thing like "Test" I will still get the same error.
得到这个奇怪的错误。我正在学习 javaScript 并从某处复制代码并运行它但出现错误。这是代码。将空字符串更改为“测试”之类的任何其他内容，我仍然会遇到相同的错误。
<script>
function theAge() {
var message, x;
message = document.getElementById("message");
message.innerHTML = "";
x = document.getElementById(age).value;
try {
x=Number(x);
if(x=="") throw "is empty";
if(isNaN(x)) throw "is not a number";
if(x>10) throw "is too high";
if(x<5) throw "is too low";
}
catch (err) {
message.innerHTML = "input" + err;
}
}
</script>
回答by Michael Coleman
Looks like you have a typo here
看起来你在这里有一个错字
x = document.getElementById(age).value;
try
尝试
x = document.getElementById("age").value;
回答by nanndoj
You must have an element for message and one for age in your html. And also put the age term between ""
您的 html 中必须有一个用于消息的元素和一个用于年龄的元素。并且还把年龄术语放在""
HTML Example:
HTML 示例：
<div>
Age: <input type="text" id="age" /> </br>
Message: <div id="message"> </div> </br>
<button onclick="theAge()">Click</button>
</div>
JS code
JS代码
function theAge() {
var message, x;
message = document.getElementById("message");
message.innerHTML = "";
x = document.getElementById("age").value;
try {
x=Number(x);
if(x=="") throw "is empty";
if(isNaN(x)) throw "is not a number";
if(x>10) throw "is too high";
if(x<5) throw "is too low";
}
catch (err) {
message.innerHTML = "input" + err;
}
}
回答by Ershad
you are using server control... use jQuery method
您正在使用服务器控件...使用 jQuery 方法
$("#controlID").html();
$("#controlID").html();
