javascript - How to apply a class to a specified grouping of characters in a string? -

trying reduce html in document applying class specific group of characters. in example group of asterisks, appear in document ** , code wrapped in

<span class="asterisk">**</span> 

but there on 50 instances on page. looking way have class added dynamically defined group, in case **

thus far efficient solution has been suggested was

<script>   $("span:contains('**')").addclass("asterisk"); </script> 

which reduces amount of code needed , brings <span>**</span>

in example below if wanted '**' indicate food items , given class do

<span>**</span>indicates food related word <p>intelligentsia high life shoreditch keffiyeh skateboard, hoodie master cleanse helvetica. fanny pack <span>**</span>raw denim street art, wes anderson gentrify lomo lo-fi. </p> <p>selfies typewriter haven't heard of them <span>**</span>small batch street art, cliche raw denim try-hard sartorial cardigan pitchfork. forage flannel portland, small batch before sold out +1 post-ironic <span>**</span>pbr skateboard mixtape fap try-hard banjo bicycle rights. vinyl banksy banjo, <span>**</span>gastropub <span>**</span>four loko art party <span>**</span>food truck next level.</p>  

see how can repetitive? intent type in '**' next want selected. , class dynamically added defined grouping of characters.

<p>**chambray letterpress **kale **chips **high life 90's wolf yr semiotics mcsweeney's biodiesel, flannel fixie retro.</p>  <p>meh wayfarers fap scenester retro single-origin **coffee, cliche craft **beer 8-bit lo-fi selvage yr mixtape 90's.</p> 

could use narrowing down go here finish up.

the clearest way use .addclass specify class name(s) want add:

$("span:contains('**')").addclass("asterisk"); 

addclass can accept function, advanced use, when want treat each element in jquery set differently. since want same thing each element, .addclass not need function.