JSFiddle - React, Tailwind, and code Playground
HTML
<textarea name="area1" cols="40" id="test22"></textarea>
<button onclick="document.getElementById('test22').select();">CLICK</button>
CSS
#test22::selection {
background:#0F0;
color:#fff;
}
JavaScript
function test(){
document.getElementById('test22').setSelectionRange(0, this.value.length)
}