Sharepoint calendar alert when event set to past date

Question

hello i want to see an alert from browser for Sharepoint online event calendar.. how can i do this ? When i add an event set to past date then an alert warns me "past day event" later open to new event modal.. *with pure script. Does anyone do similar?

Answer 1

hello everyone i solved the problem, First of all, I would like to point out that we need to write the script we are going to write inside the modal. script:

<script>
function PreSaveItem() {

var UserDate = document.getElementById("ctl00_ctl34_g_edc3892a_ea11_4e2e_b0e6_1943c7cef962_ctl00_ctl05_ctl03_ctl00_ctl00_ctl05_ctl00_ctl00_DateTimeField_DateTimeFieldDate").value;

var UserDateReverse = UserDate.split(".").reverse();

var dd1 = String(UserDateReverse[2]).padStart(2, '0');
var mm1 = String(UserDateReverse[1]).padStart(2, '0');
var yyyy1 = String(UserDateReverse[0]).padStart(2, '0');

var selectDate = yyyy1 + mm1 + dd1;

var today = new Date();
    
var dd = String(today.getDate()).padStart(2, '0');
var mm = String(today.getMonth() + 1).padStart(2, '0'); //January is 0!
var yyyy = String(today.getFullYear());

today = yyyy + mm + dd;  

    if (selectDate < today) {
          alert("past day event!!!");
          return false;
     } 
    return true;

}
</script>

I found PreSaveItem() function for save new event button.