mfrachet

JavaScript knowledge

• Operators, operands, operator precedence (unary, binary, ternary)
• Dynamic Type system: types and conversion
  • Value type vs. Reference type
• Expression vs. Statement
• Scope
• Hoisting
• Overloading
• Prototypal inheritance vs. Classical inheritance
• Instancing

mfrachet

What forces layout / reflow

All of the below properties or methods, when requested/called in JavaScript, will trigger the browser to synchronously calculate the style and layout*. This is also called reflow or layout thrashing, and is common performance bottleneck.

Element

Box metrics

• elem.offsetLeft, elem.offsetTop, elem.offsetWidth, elem.offsetHeight, elem.offsetParent
• elem.clientLeft, elem.clientTop, elem.clientWidth, elem.clientHeight
• elem.getClientRects(), elem.getBoundingClientRect()