document.GetElementById不适用于任何类型的浏览器
[英]document.GetElementById doesn't work in any kind of browser
问题描述
I'm trying to get the value of an input (text/textarea) and document.getElementById('rtext').value returns nothing. 
我正在尝试获取输入（text / textarea）和document.getElementById('rtext').value什么都不返回。 If I set a default value (value="XXX"), it returns that value, eve if i edit it. 如果我设置了默认值（value =“XXX”），则返回该值，如果我编辑它，则返回。
Here's some sample: 这是一些示例：
<div class="forms">
<p><textarea id='rtext'></textarea></p>
</div>
I'm mentioning that the form element <textarea> isn't part of any form and i'm forced to use only document.getElementById . 我提到表单元素<textarea>不是任何表单的一部分，我被迫只使用document.getElementById 。 No jQuery and no this.form.Id.value 没有jQuery，也没有this.form.Id.value
Please help. 请帮忙。 THX 谢谢
8 个解决方案
解决方案1
5 2010-09-22 13:27:54
getElementById() (case is important) is a member of the document object. getElementById（） （大小写很重要）是文档对象的成员。 To call the function, you need to refer to the object and then the function. 要调用该函数，您需要引用该对象，然后引用该函数。 In dot notation, it should be: 点符号，应该是：
document.getElementById()
document.getElementById() - MDC document.getElementById（） - MDC
Note that IDs must be unique on the page and having another element with the same ID might be causing your issue. 请注意，页面上的ID 必须是唯一的 ，并且具有相同ID的其他元素可能会导致您的问题。
解决方案2
2 2010-09-22 13:27:39
好吧，它是document.getElementById() ，innit？
解决方案3
1 2010-09-22 14:05:10
Works for me: 适合我：
<div class="forms">
<p><textarea id='rtext'></textarea></p>
</div>
<input type = "button"
onclick = "alert(document.getElementById('rtext').value);"
value = "run" />
<a href = "javascript:void(0);"
onclick = "alert(document.getElementById('rtext').value)"
>GET</a>
Things to consider: 需要考虑的事项：
- Make sure the code is being called; 确保调用代码; there may be errors in your JavaScript 您的JavaScript可能存在错误
- Make sure the id is unique to the HTML/DOM as Andy E has pointed out, though I think the function will grab the first object it finds, if there are multiple. 确保id对于HTML / DOM是唯一的，正如Andy E指出的那样，尽管我认为该函数将抓取它找到的第一个对象，如果有多个。
- Make sure the spelling/case is correct; 确保拼写/案例正确无误;
getElementById()andgetElementByID()are not the same functiongetElementById()和getElementByID()不是同一个函数 - Make sure you're trying to grab the value after it is populated using the correct event (
onkeyupvsonkeypress)确保在使用正确的事件（ onkeyupvsonkeypress）填充后尝试获取值
解决方案4
1 已采纳 2010-09-22 14:14:40
Try to put your code snippet at the end of your <body> tag. 尝试将代码段放在<body>标记的末尾。 Your javascript is probably executing before your <textarea> element has loaded. 您的javascript可能在 <textarea>元素加载之前执行。
So: 所以：
<html>
<body>
<div class="forms">
<p><textarea id='rtext'></textarea></p>
</div>
<script type="text/javascript">
var el = document.getElementById('rtext');
alert(el);
</script>
</body>
</html>
(I've left out the head and other tags to keep it compact :) （我遗漏了头部和其他标签以保持紧凑:)
解决方案5
1 2010-09-22 15:02:27
I solved the problem: 我解决了这个问题：
I inserted the form tags, I modified the 我插入了表单标签，我修改了
<a href="javascript"
onclick="alert(document.getElementById('rname').value)">GET</a>
with 同
<input type="button"
onclick="document.getElementById('rname').value=this.form.rname.value" />`
It works fine now. 它现在工作正常。
解决方案6
1 2010-09-22 15:04:11
你有没有尝试过：
document.getElementById('rtext').textContent
解决方案7
0 2010-09-22 14:11:55
Since you've tried everyone's solutions and you can't find the error I would suggest that you try debugging the JavaScript in your browser. 既然你已经尝试过每个人的解决方案而你找不到错误，我建议你尝试在浏览器中调试JavaScript。
In IE8 (I don't remember if 7 had it) hit F12 and bring up the developer toolbar. 在IE8中（我不记得7是否有它）点击F12并调出开发人员工具栏。 On the script tab you can test your javascript by hand in the console or debug it. 在脚本选项卡上，您可以在控制台中手动测试您的javascript或进行调试。
In FireFox use Firebug. 在FireFox中使用Firebug。
In Chrome hit Ctrl+Shift+J, the console will be at the bottom of the screen. 在Chrome中按Ctrl + Shift + J，控制台将位于屏幕底部。 You can also debug the scripts on the scripts tab. 您还可以在脚本选项卡上调试脚本。
解决方案8
0 2010-09-22 14:34:58
If you are using the Text element within an Update Panel then the Id being rendered on the page is no longer rtext .Only if you are using an Update Panel. 如果您在更新面板中使用Text元素，则在页面上呈现的Id不再是rtext。仅在您使用更新面板时。 DO a view source code to verify if the ID is retained as rtext 查看源代码以验证ID是否保留为rtext
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