Task: Create simple context menu on pure JavaScript.

Requirements:

• You can`t use any libraries - only pure JS

• menu should be configurable (for example JSON)

  • config options
    • element on which will appear context menu
    • menu items
    • item click handler
    • item title
    • item can be disabled
    • may be a submenu

• if you click another place except menu it should close

• menu should appear near the cursor when right mouse button is clicked

  • scrolling should happen when user click up/down arrow when up/down arrow clicked menu must scroll by 1 item up/down
  • If the menu does not fit into the screen custom scroll should appear

• If it's not possible to expand menu down / right side it should be expanded up / left and vise versa
• solution should be cross-browser (Chrome, Firefox, IE11+)