javascript regex replace the space between two groups -

i programmatically modifying large text file containing html/js code , need "mark" locations there space between 2 selectors, such between id , classname, in $('#btnone .subelement'). find these, need regex. however, falling down on replace bit.

regex101 demo -- correctly identifies 2 examples need replace inside space marker (such $#$#$ or something). (what wrong regex101 demo entire substring matched, not space in middle - that's need replace)

here code snippet replace ready go, same problem above.

$('button').click(function(){  	var tmp = $('#orig').text();  	tmp = tmp.replace("<br>", "\n");  	tmp = tmp.replace(/\$\(['"].+ .*\)\./gi,'<span>how_target_only_the_space_char?</span>.');    $('#output').html(tmp);  });

#output{margin-top:10px;background:palegoldenrod;}  span{color:brown;font-weight:bold;}

<script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.1/jquery.min.js"></script>  <div id="orig">  function initsxschartbtns(){<br>  	var onebtnisalreadyclicked = false;  	$('#databuttons button').each(function(){  		if ( $(this).hasclass('btn_depressed') ) onebtnisalreadyclicked = true;  	});  	if (!onebtnisalreadyclicked){  		$('#txtadvisory').val('approximately 25% registered.');  		$('#btnone .subelement').addclass('btn_depressed');  		$('#btntwo.sameelement').addclass('btn_depressed');  	}  }  </div>  <button>regex replace</button>  <div id="output"></div>

you this:

tmp = tmp.replace(/(\$\(['"].+) (.*\)\.)/gm, '$1abc$2'); 

here $1 , $2 used refer capture groups in regexp. i've tried changed regexp little possible, i've added parentheses create capture groups.

replace allows pass function second argument, allowing control replacement more precisely.

https://developer.mozilla.org/en-us/docs/web/javascript/reference/global_objects/string/replace