JSFiddle - React, Tailwind, and code Playground

HTML

<input type="text" value="0" class="dp2" />

JavaScript

function trimDP(x, dp) {
    x = parseFloat(x);
    if (dp === 0)
        return Math.floor(x).toString();
    dp = Math.pow(10, dp || 2);
    return (Math.floor((x) * dp) / dp).toString();
}


window.addEventListener('load', function () {
    var nodes = document.querySelectorAll('.dp2'), i;
    function press(e) {
        var s = String.fromCharCode(e.keyCode);
        if (s === '.')
            if (this.value.indexOf('.') === -1)
                return; // permit typing `.`
        this.value = trimDP(this.value + s);
        e.preventDefault();
    };
    function change() {
        this.value = trimDP(this.value);
    }
    for (i = 0; i < nodes.length; ++i) {
        nodes[i].addEventListener('keypress', press);
        nodes[i].addEventListener('change', change);
    }
});