The JavaScript warning "test for equality (==) mistyped as assignment (=)?" occurs when there was an assignment (=) when you would normally expect a test for equality (==).

The JavaScript exception "unlabeled break must be inside loop or switch" occurs when a break statement is not inside a loop or a switch statement.

The startOffset attribute defines an offset from the start of the path for the initial current text position along the path after converting the path to the <textPath> element's coordinate system.

The Set object lets you store unique values of any type, whether primitive values or object references.

The horiz-adv-x attribute indicates the horizontal advance after rendering a glyph in horizontal orientation.

The font-size-adjust attribute allows authors to specify an aspect value for an element that will preserve the x-height of the first choice font in a substitute font.

Number values represent floating-point numbers like 37 or -9.25.

The dy attribute indicates a shift along the y-axis on the position of an element or its content.

The decoding attribute, valid on <image> elements, provides a hint to the browser as to whether it should perform image decoding along with rendering other content in a single presentation step that looks more "correct" (sync), or render and present the other content first and then decode the image and present it later (async). In practice, async means that the next paint does not wait for the image to decode.

The dx attribute indicates a shift along the x-axis on the position of an element or its content.