<input type="password" placeholder="Enter Mobile no" formControlName="mobile_no" (keydown)="validateNumber($event)">
validateNumber(event) { const keyCode = event.keyCode; const excludedKeys = [8, 37, 39, 46]; if (!((keyCode >= 48 && keyCode <= 57) || (keyCode >= 96 && keyCode <= 105) || (excludedKeys.includes(keyCode)))) { event.preventDefault(); } }