javascript regular expression replace in input form validation

Question

When inputting a string with a format:

the beginning r or R, then some non-digit letters, I want to replace the string with R.

It's in this situation:

onkeyup="this.value=this.value.replace(/^[rR]\D/g,'R')"

But it does not work.

Somebody can help me out? Thanks.

@ArunPJohny's jsfiddle does work for me (testing on Chrome). You don't even need the g modifier, since a regex which starts at ^ will match at most once (no multiple substitutions necessary). — rplantiko
– rplantiko, Commented Aug 17, 2015 at 6:11
/^/ never requires the g flag, how many "start of strings" are there? ;-) — RobG
– RobG, Commented Aug 17, 2015 at 6:15

cнŝdk · Accepted Answer · 2015-08-17 07:12:18Z

2

Use the following regex:

     onkeyup="this.value=this.value.replace(/^[rR]\D+/, 'R')";

See this DEMO:

<input onkeyup="this.value=this.value.replace(/^[rR]\D+/,'R')" />

answered Aug 17, 2015 at 6:00

cнŝdk

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2 Comments

Thanks, chsdk. It's what I want. And @ArunPJohny 's answer also works fine. Thank all of you.

Great, glad it helps.