JSFiddle - React, Tailwind, and code Playground
HTML
<input type="text" value="">
CSS
.class_for_watermark {
background-color: green;
}
JavaScript
$('input[type=text]').on('keyup', function() {
var targetInput = this; // keeping reference of input
if ($.trim(this.value).length) {
// code for remove watermark
$(targetInput).addClass('class_for_watermark');
} else {
// code for add watermark
$(targetInput).removeClass('class_for_watermark');
}
});