Check Number of notes attached to a Crm Record.

Write below code on save of the entity.

var CRM_FORM_TYPE_CREATE = 1;

if (crmForm.FormType == CRM_FORM_TYPE_CREATE)

{

    var obj=document.frames(”notescontrol”).document;

    var textarea=obj.getElementsByTagName(’TEXTAREA’);

    if (textarea.length < 1)

    {

        alert (”please eneter somenotes”);

        // Cancel the save

        event.returnValue = false;

    }

}