在输入的属性“模式”上使用星号是什么意思？

Question

Here's an example: 这是一个例子：

<input title="Only numbers" pattern="[0-9]*" type="text" />

I would like to know what implies using * in pattern="[0-9]*" 我想知道在pattern="[0-9]*"使用*含义

Thanks! 谢谢！

Answer 1

* means 0 or more of the previous item, in this case digits 0-9. *表示前一项的0或更多，在这种情况下为数字0-9。

This means the empty string will also be allowed as well as "0", "12" etc.. 这意味着也将允许使用空字符串以及“ 0”，“ 12”等。

Other quantifiers exist, like + means 1 or more etc... 存在其他量词，例如+表示1或更多，等等。

There are many tutorials out there, but you can't go wrong with Wikipedia 那里有很多教程，但是Wikipedia不会出错

In your case, I'd recommend using the built-in number type instead as the intent is clearer... 在您的情况下，建议您改用内置数字类型，因为意图更清晰...

<input title="Only numbers" type="number" />