sublimetext2 - Replacing an open-ended HTML regex match in Sublime Text -

i've been doing lot of finding , replacing in sublime text , decided needed learn regex. far, good. i'm no expert means, i'm learning quickly.

the trouble knowing how replace open-ended html matches.

for example, wanted find <button>s didn't have role attribute. after hacking , searching, came following pattern (see in action):

<button(?![^>]+role).*?>(.*?)

great! except, in code base i'm working in, there tons of results.
how do replacing results safely injecting role=button @ end of <button, before closing > in opening tag?

desired results
before: <button type="button">
after: <button type="button" role="button">

before: <button class="btn-lg" type="button">
after: <button class="btn-lg" type="button" role="button">

you can capture before ending > , put back, before insertion of role=button:

<(button(?![^>]+role).*?)> 

this captures in tag.

replace by:

<$1 role="button"> 

the $1 contains first regex captured.

see updated regexr.