regex101: background:url

Group 1(background:\s*url\((https?:\/\/)*([a-zA-Z0-9._:\/\s*]*)\)\s*[a-zA-Z0-9\s*-._:\/;]*)

background:the literal text background: (case sensitive)

\s*any whitespace character, repeated any number of times

urlthe literal text url (case sensitive)

\(the literal ( (40₁₀ / 50₈ / 28₁₆)

Group 2(https?:\/\/)*

*repeats the group contents below any number of times:

httpthe literal text http (case sensitive)

s?optionally matches the literal s (115₁₀ / 163₈ / 73₁₆) (case sensitive)

:the literal : (58₁₀ / 72₈ / 3A₁₆)

\/the literal / (47₁₀ / 57₈ / 2F₁₆)

Group 3([a-zA-Z0-9._:\/\s*]*)

Character Class[a-zA-Z0-9._:\/\s*]*

*matches any number of characters from the set below:

a-zone character from a (97₁₀) to z (122₁₀) (case sensitive)

A-Zone character from A (65₁₀) to Z (90₁₀) (case sensitive)

0-9one character from 0 (48₁₀) to 9 (57₁₀)

.the literal . (46₁₀ / 56₈ / 2E₁₆)

_the literal _ (95₁₀ / 137₈ / 5F₁₆)

:the literal : (58₁₀ / 72₈ / 3A₁₆)

\/the literal / (47₁₀ / 57₈ / 2F₁₆)

\sany whitespace character

*the literal * (42₁₀ / 52₈ / 2A₁₆)

\)the literal ) (41₁₀ / 51₈ / 29₁₆)

\s*any whitespace character, repeated any number of times

Character Class[a-zA-Z0-9\s*-._:\/;]*

*matches any number of characters from the set below:

a-zone character from a (97₁₀) to z (122₁₀) (case sensitive)

A-Zone character from A (65₁₀) to Z (90₁₀) (case sensitive)

0-9one character from 0 (48₁₀) to 9 (57₁₀)

\sany whitespace character

*-.one character from * (42₁₀) to . (46₁₀)

_the literal _ (95₁₀ / 137₈ / 5F₁₆)

:the literal : (58₁₀ / 72₈ / 3A₁₆)

\/the literal / (47₁₀ / 57₈ / 2F₁₆)

;the literal ; (59₁₀ / 73₈ / 3B₁₆)

Global pattern flags

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

25 tokens

Regular Expression

(background:\s*url\((https?:\/\/)*([a-zA-Z0-9._:\/\s*]*)\)\s*[a-zA-Z0-9\s*-._:\/;]*)

New

.nyroModalCloseButton {
	top: -13px;
	right: -13px;
	width: 12px;
	height: 12px;
	text-indent: -9999em;
	background: url(http://instantcms.ru/templates/_default_/images/nyromodal/close.gif) no-repeat 6px center;
}

.nyroModalCloseButton {
	top: -13px;
	right: -13px;
	width: 12px;
	height: 12px;
	text-indent: -9999em;
	background: url(https://instant/templates/_default_/images/nyromodal/close.gif);
}
.nyroModalCloseButton {
	top: -13px;
	right: -13px;
	width: 12px;
	height: 12px;
	text-indent: -9999em;
	background: url(../instant/templates/_default_/images/nyromodal/close.gif);
}

Extraction

.nyroModalCloseButton {
	top: -13px;
	right: -13px;
	width: 12px;
	height: 12px;
	text-indent: -9999em;
	background: url(http://instantcms.ru/templates/_default_/images/nyromodal/close.gif) no-repeat 6px center;
}

.nyroModalCloseButton {
	top: -13px;
	right: -13px;
	width: 12px;
	height: 12px;
	text-indent: -9999em;
	background: url(https://instant/templates/_default_/images/nyromodal/close.gif);
}
.nyroModalCloseButton {
	top: -13px;
	right: -13px;
	width: 12px;
	height: 12px;
	text-indent: -9999em;
	background: url(../instant/templates/_default_/images/nyromodal/close.gif);
}