JSFiddle - React, Tailwind, and code Playground

by vandanasrivastava

HTML

<input type='text' name='price' value='0' onkeypress='validate(event)'/>

CSS

#testinput
{
    margin: 15px;
    font-size: 20px;
}

#result
{
    font-family: 'Microsoft Sans Serif', 'Verdana', 'Helvetica';
    font-size: 20px;
}

#result.valid
{
    color: green;
}

#result.invalid
{
    color: red;
}

JavaScript

function validate(evt)
{
    if(evt.keyCode!=8)
    {
        var theEvent = evt || window.event;
        var key = theEvent.keyCode || theEvent.which;
        key = String.fromCharCode(key);
        //var regex = /[0-9]|\./;
        var regex = /(0?[1-9]|1[012])/;
        if (!regex.test(key))
        {
            theEvent.returnValue = false;

            if (theEvent.preventDefault)
                theEvent.preventDefault();
            }
        }
    }