Regular Expressions 101

1st Alternative(?:src|href)="[^ "]*\K

Non-Capturing Group(?:src|href)

1st Alternativesrc

srcthe literal text src (case sensitive)

2nd Alternativehref

hrefthe literal text href (case sensitive)

="the literal text ="

Negated Character Class[^ "]*

*matches any number of characters outside the set below:

the literal (32₁₀ / 40₈ / 20₁₆)

"the literal " (34₁₀ / 42₈ / 22₁₆)

\Kresets the starting point of the reported match. Any previously consumed characters are no longer included in the final match

the literal (32₁₀ / 40₈ / 20₁₆)

2nd Alternative\G(?!\A)[^ "]*\K

\Gstart of current search

Negative Lookahead(?!\A)

\Astart of string

Negated Character Class[^ "]*

*matches any number of characters outside the set below:

the literal (32₁₀ / 40₈ / 20₁₆)

"the literal " (34₁₀ / 42₈ / 22₁₆)

\Kresets the starting point of the reported match. Any previously consumed characters are no longer included in the final match

the literal (32₁₀ / 40₈ / 20₁₆)

Global pattern flags

g modifier: global. Finds all matches instead of stopping after the first

Detailed match information will be displayed here automatically.

Search reference

Regular Expression

(?:src|href)="[^ "]*\K |\G(?!\A)[^ "]*\K

в последовательностях вида src="qqq www ee" и href="fewfwe e fe" и заменяет
src="jhbgsc sdhjgsj hgj"

_