JSFiddle - React, Tailwind, and code Playground

HTML

<div id="foo">
   <div id="line1">...</div>
   <div id="line2"></div>
</div>

CSS

#line2 > input {
    border     : none;
    background : transparent;
}

JavaScript

var $foo   = $('#foo'),
    $line2 = $foo.children('#line2');

if ($line2.length == 0) {
    //no #line2 element is found
    $foo.append('<div id="line2">new</div>');
} else if ($line2.text().length == '') {
    //#line2 element is empty
    $line2.text('new');
} else if ($line2.text() != 'foobar') {
    //#line2 element does not contain only the string: foobar
    $line2.text('new');
}