如何检查用户是否在Javascript中输入了日期值？

Question

I am trying to develop a system which checks if the date is entered by the user or not, however when ever i try to use these if(!date){//code} or if(date.length==0) i don't get what i want, maybe because <input type="date"> execute input feild with dd-----yyyy and a celender in the browser which is counted as a value in js.

So my question is to get 1 if the date is entered by the user and 0 if user leaves the field empty or default ( dd-----yyyy and a celender ).

Answer 1

You Have To Use

if(date.value.length == 0)

Not

if(date.length==0)

 var f = document.querySelector("form"); f.addEventListener("submit", function(e){ var d = document.getElementById("date"); if(d.value.length < 1){ alert("Date Is Required"); e.preventDefault(); } });

 <form> <input type="date" id="date" name="date"> <button>Go</button> </form>

Or Try This way

 var f = document.querySelector("form"); f.addEventListener("submit", function(e){ const d = document.getElementById("date"); if(!d.checkValidity()){ alert("Date Is Required"); e.preventDefault(); } });

 <form novalidate> <input type="date" id="date" name="date" required> <button>Go</button> </form>