JSFiddle - React, Tailwind, and code Playground

HTML

<div id="container">
    A text outside any tag<br/>
    <input type="button" id="iii" value="xxx"/>
    Another text<br/>
    <a href="#">A link</a>
</div>

CSS

#container {
    border: 1px solid red;
}

.hidden{
    display: none;
}

JavaScript

var allNodes = document.getElementById("container").childNodes;
for (i = 0; i < allNodes.length; i++) {
    var item = allNodes[i];
    
    if(item.tagName){
    	// It already has a proper tag, so just hide it with a class
        $(item).addClass("hidden");
    }else{
    	// Add a span around it, then hide it
        $(item).wrap("<span class='hidden'>");
    }
}

$("#container #iii").removeClass("hidden");