javascript '无法设置未定义的属性“innerHTML”'
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'Cannot set property "innerHTML" of undefined'
提问by Sean P. McMullen
I'm trying to write a pretty simple script to set an element's innerHTML to the time. However, Javascript keeps throwing a "Cannot set property 'innerHTML' of undefined" error. During debugging, I've simplified my script to the point that it runs right after element (a <span>) is coded, so I know it should have loaded already. I've also tried running this script as a <body onload=argument - same error. I can't tell what I'm doing wrong.
我正在尝试编写一个非常简单的脚本来将元素的innerHTML 设置为时间。但是，Javascript 不断抛出“无法设置未定义的属性‘innerHTML’”错误。在调试期间，我已将脚本简化为在元素 (a <span>) 编码后立即运行，因此我知道它应该已经加载了。我也试过将此脚本作为<body onload=参数运行- 同样的错误。我说不出我做错了什么。
<div style="position: fixed; right: 10px; top: 10px; width: auto; font-size: 16pt; border: 2px solid #000000;">
<span id="clock">Loading...</span>
<script type="application/x-javascript">
function setClock(spanid){
var d = new Date();
document.getElementById[spanid].innerHTML = d.getHours() + ":" + d.getMinutes() + ":" + d.getSeconds;
}
setClock("clock");
</script>
</div>
Any help is appreciated!
任何帮助表示赞赏！
回答by Chris Hayes
You are not calling getElementById, you are attempting to index it. Since it is not an array and does not expose array-like behavior, the result is undefined. Replace your getElementById[spanId]with getElementById(spanId).
您不是在调用getElementById，而是试图对其进行索引。由于它不是数组并且不公开类似数组的行为，因此结果是undefined. 替换你getElementById[spanId]的getElementById(spanId)。
回答by Arun P Johny
[]instead of ()in document.getElementById(spanid). getElementByIdis function, it has to be invoked with ()and pass the parameter inside it.
[]而不是()在document.getElementById(spanid)。getElementById是函数，它必须被调用()并在其中传递参数。
Also missing ()after getSeconds()
也失踪()后getSeconds()
<div style="position: fixed; right: 10px; top: 10px; width: auto; font-size: 16pt; border: 2px solid #000000;">
<span id="clock">Loading...</span>
<script type="application/x-javascript">
function setClock(spanid){
var d = new Date();
document.getElementById(spanid).innerHTML = d.getHours() + ":" + d.getMinutes() + ":" + d.getSeconds();
}
setClock("clock");
</script>
</div>
Demo: Fiddle
演示：小提琴
回答by Unknown
change []to ():
更改[]为()：
function setClock(spanid){
var d = new Date();
document.getElementById(spanid).innerHTML = d.getHours() + ":" + d.getMinutes() + ":" + d.getSeconds;
}
回答by Thanos
And now that you have this fixxed add this:
现在你有了这个固定的添加这个：
setInterval(function () {
function setClock(spanid) {
var d = new Date();
document.getElementById(spanid).innerHTML = d.getHours() + ":" + d.getMinutes() + ":" + d.getSeconds();
}
setClock("clock");
}, 1);
And you have an actual clock :D
你有一个实际的时钟：D
