Question

I want to create a html form with a text-field which checks if DD-MM-YYYY are correctly entered into the field and alerts the user if it’s not the case. How can i approach this with javascript?

Answer 1

In JS, after the user key’s off or hits enter, you could test the value (assuming the <input> has an id of inpdate for sake of example):

var val = document.getElementById('inpdate').value;
var check = /^\s*\d{2}-\d{2}-\d{4}\s*$/;
if(check.test(val)){
    // it's good
}
else {
    // not valid
}

I put \s* in to allow leading and trailing whitespace. Up to you if you would want to allow that.