JSFiddle - React, Tailwind, and code Playground

by Shef

JavaScript

function isGoodDate(dt){
    var reGoodDate = /^(?:(0[1-9]|1[012])[\/.](0[1-9]|[12][0-9]|3[01])[\/.](19|20)[0-9]{2})$/;
    return reGoodDate.test(dt);
}

var first = '06/01/2011',
    second = '1/3/2011',
    third = '06-01-2011';

if(!isGoodDate(first)){
   alert("First date not in correct format of MM/dd/YYYY");
}

if(!isGoodDate(second)){
   alert("Second date not in correct format of MM/dd/YYYY");
}

if(!isGoodDate(third)){
   alert("Third date not in correct format of MM/dd/YYYY");
}