RegEx to validate date

Regular expression used to validate a date.

HTML

<input type="text" id="date" name="date" value="dd/mm/yyyy" />
<button onclick="isDate();">Check</button>

<p id="response"></p>

JavaScript

function isDate() {
    
    var regex = /^(((0[1-9]|[12]\d|3[01])\.(0[13578]|1[02])\.((19|[2-9]\d)\d{2}))|((0[1-9]|[12]\d|30)\/(0[13456789]|1[012])\/((19|[2-9]\d)\d{2}))|((0[1-9]|1\d|2[0-8])\.02\.((19|[2-9]\d)\d{2}))|(29\/02\/((1[6-9]|[2-9]\d)(0[48]|[2468][048]|[13579][26])|((16|[2468][048]|[3579][26])00))))$/g;
    
    var txt = document.getElementById("date").value;
    var p = document.getElementById("response");
    
    p.innerHTML = (regex.test(txt)) ? 
        "<h1 style='color:green'>Correct</h1>" : "<h1 style='color:red'>Wrong</h1>";
    
}