为什么我不能使用 - 在字段名称？
[英]Why can't I use - in field names?
问题描述
Basically I'm just trying to clear a text field, which has never been a problem for me. 
基本上我只是想清除一个文本字段，这对我来说从来都不是问题。 However, this is NOT working: 但是，这不起作用：
<html>
<body>
<form name="form">
<input type="text" name="input-field" value="Value" />
<input type="button" name="clear" value="Clear field" onclick="document.form.input-field.value = ''"; />
</form>
</body>
</html>
But if I rename "input-field" to "inputfield" and onclick to onclick="document.form.inputfield.value = ''"; 但是，如果我将“input-field”重命名为“inputfield”并onclick to onclick =“document.form.inputfield.value =''”; ... Then it works fine. ...然后它工作正常。
However... Removing the "-" from the field name, is not an option in my case (long explanation). 但是...从字段名称中删除“ - ”，在我的情况下不是一个选项（长解释）。
So, how do I clear a text field, containing a "-"??? 那么，如何清除包含“ - ”的文本字段？
2 个解决方案
解决方案1
10 已采纳 2012-09-08 23:49:16
Because it's not a valid JavaScript identifier. 因为它不是有效的JavaScript标识符。 However, you can use the following instead: 但是，您可以使用以下代码：
document.form['input-field'].value
It's for the same reason you can't declare a variable using var my-var . 出于同样的原因，您无法使用var my-var声明变量。 On the other hand, if you have an object , such as form with several keys, you can access its properties as if it was an associative array: 另一方面，如果您有一个object ，例如具有多个键的form ，则可以像访问关联数组一样访问其属性：
var form = {
"input-field": 20,
otherKey: 30
};
form.input-field; // Error
form.otherKey; // OK
form['input-field']; // OK
References: 参考文献：
- Identifier Names and Identifiers (ECMAScript Language Specification) 标识符名称和标识符 （ECMAScript语言规范）
- Objects as associative arrays 对象作为关联数组
解决方案2
6 2012-09-08 23:52:17
- is not a valid character in an identifier because, for example - ，不是标识符中的有效字符
document.form.input-field;
is interpreted as 被解释为
document.form.input - field;
Of course you can remedy the problem by using the square bracket notation: 当然，您可以使用方括号表示法来解决问题：
document.form["input-field"];
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