Open SharePoint List Items in Edit Mode by Default

Requirement: Open SharePoint Task list items in Edit form directly instead of "Display form".

Solution:

1. Go to your SharePoint task list, Click on Site settings gear, Choose "Edit page" 
2. Add a script editor and place this code:
   
   jQuery to launch list items in Edit mode:

   <script type="text/javascript" src="https://ajax.googleapis.com/ajax/libs/jquery/1.4.4/jquery.min.js"></script>
   <script type="text/javascript">
   $(document).ready(function() 
   {
     //Change display form links to edit form links
     $('.ms-vb a[href*="listform.aspx"]').each(function(){
         var url = $(this).attr('href');
         url = url.replace("PageType=4", "PageType=6");
         $(this).attr('href', url);
     });
   });
   </script>

3. Save and close!

Now, on clicking any task item link, you'll be taken into Edit form directly.