JSFiddle - React, Tailwind, and code Playground
HTML
<div id="outer">
<div id="inner-1 html">
Test
</div>
</div>
JavaScript
var x = 'inner-1 html';
var y = $('#outer').find('[id^="' + x + '"]');
alert(y);
<div id="outer">
<div id="inner-1 html">
Test
</div>
</div>
var x = 'inner-1 html';
var y = $('#outer').find('[id^="' + x + '"]');
alert(y);