Grasemonkey - how to add code to a webpage when certain text appears?

<div id="someid" class="someclass" style=""></div>

<div id="someid" class="someclass" style="">Some text here...</div>

<div id="idbla">This is text...</div>

// ==UserScript==
// @name        Nameo
// @include     https://link.o
// @require     http://ajax.googleapis.com/ajax/libs/jquery/1.7.1/jquery.min.js
// @grant       GM_addStyle
// ==/UserScript==
/*- The @grant directive is needed to work around a design change
introduced in GM 1.0.   It restores the sandbox.
 */

var intv = setInterval(function() {
    
if (/(containerimg)|(currently)/i.test (document.body.innerHTML) )

{

$("body").append (
   '<a class="classo" href="#">texto</a>'
);
 
}
    
    }, 3000);