Question

I am trying to update a substring in textarea. Basically, its a twitter like @username feature. User will type in @user and I have to replace “@user..” with user’s selected username.

String:

Hello this is [e-mail] and @gma

In above string, the focus is at the end of string i., after @gma.
I would like to replace @gma with my choice of substring. Somehow, I am not able to do it.
When I use

this.value = this.value.replace("@gma"+"", "ReplaceText") + ' ';

the @gma of the [e-mail] is replaced. How do I change the recently typed @gma?

I can get the caret position, but not able to replace the required substring.

Any help would be appreciated.

Answer 1

You’ll want to use RegEx instead of a normal string for the replacement.

this.value = this.value.replace(new RegExp("@gma$","g"), "ReplaceText") + ' ';

The important part is the $ sign, which means to search for @gma only at the end of the string. If you want to replace any alphanumeric string after the last @ sign:

this.value = this.value.replace(
    new RegExp("@[A-Za-z0-9]+$","g"), 
    "ReplaceText") 
+ ' ';