type: utility
release: 1.8
status: released
documentation: http://api.jqueryui.com/position/
demo: http://jqueryui.com/position/
1 - Description:
Utility script for positioning any widget relative to the window, document, a particular element, or the pointer. This utility could be used on its own, but should also be used by all plugins that require positioning elements. A few examples are:
- menus: (menu's left top at left bottom of menu button) A standard menu opens directly below the bottom left corner of the target and the menu itself would be aligned top left.
- tooltip: (tooltip's left bottom at center top of element/cursor) If the link or element is the target, you'd probably want to have the left edge of the tooltip centered horizontally above the element. If a tooltip uses the current cursor position as the target, this will cause the tooltip to be place just above and to the right of the cursor, since a cursor occupies a single pixel.
- dialog: (dialog's center at window's center) A dialog usually is centered vertically and horizontally within the window.
Positioning system:
We can use a simple system to define how the positioned element (e.g., menu or tooltip) should be placed in relation to the target element (e.g., link or button).
- The positioned element and target element both have 9 positions that map to the corners and centers of the objects.
- For these positions, we can use a CSS-style naming convention for horizontal (left, center, right) and vertical (top, center, bottom) values.
To describe the relationship between the target and positioned element, we can specify a pair of these positions:
By combining the target and positioned elements together, we arrive at 81 possible positioning combinations.
Collision detection
- If the positioned object will not safely fit in the specified horizonal or vertical position, the positioned element can:
- flip to the opposite side.
- fit so the element stays in the desired direction, but is re-positioned so it is fully visible.
- flip and fit.
- not do collision detection.
- These collision detection options should be set independently for horizontal and vertical settings.
- A user/plugin can get the collision detection to re-run when the window is resized by simply calling the plugin again with the same options in a window resize event handler.
2 - Visual Design:
N/A
3 - Functional Specifications/Requirements:
The element being positioned must support relative, absolute and fixed positioning. If the element's position style is set to static, it will be set to relative when being positioned.
4 - Markup & Style:
N/A
5 - Latest version of plugin:
http://view.jqueryui.com/master/demos/position/default.html
6 - Open issues being discussed