Javascript RegEx用下划线字符串替换单个下划线

Question

I have a textarea where the user is able to type underscores. I want to convert the underscores that they type to a string of 10 underscores. I want this to be done in real time as they type.

_ => _ ___

I had thought that I could do something as simple as:

onkeyup: textarea.value.replace(/_*/g, " _ ___ ");

My thought being that it would match any string of underscores and automatically convert them to 10 underscores.

I get really odd behavior though. Typing an underscore results in 20 underscores. Also, it seems to be matching the left and right of any character I type. For example, if I type "A", I get:

___ A _ __

Does anybody know how to get this working properly? Seems so simple yet I am stumped. Thanks.

Answer 1

Use /_+/ rather than /_*/ . * in a regexp matches zero-or-more of the character, so it's matching the empty string after the underscore and replacing it with 10 underscores. + matches one-or-more.

Answer 2

将您的模式更改为/ _ {1，} /，这将匹配_或_ ，您之前的模式将匹配_ ，之后匹配任意数量的字符。