[JSWolf]

Originally Posted by DNSB

Unfortunately, your regex does horrible things if you have nested spans:

<span class="text_14"> blah de blah de blah<span class="text_17">more blah de blah</span>yet more blah de blah</span>

which your regex would convert to:

 blah de blah de blah<span class="text_17">more blah de blah yet more blah de blah</span>

It would be much safer to simply use:

search: <span class="text_14>
replace: <span>

and then remove the naked <span> tags using Diap's "Editing Toolbag" (Calibre) / "TagMechanic" (Sigil).

That's twice the work when Diaps Editing Toolbag can do the <span class="text_14"> delete in one go.