The JavaScript exception "missing variable name" is a common error. It is usually caused by omitting a variable name or a typographic error.

The keyTimes attribute represents a list of time values used to control the pacing of the animation.

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.

The in operator returns true if the specified property is in the specified object or its prototype chain.

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

The new operator lets developers create an instance of a user-defined object type or of one of the built-in object types that has a constructor function.

The height attribute defines the vertical length of an element in the user coordinate system.

The async function declaration creates a binding of a new async function to a given name. The await keyword is permitted within the function body, enabling asynchronous, promise-based behavior to be written in a cleaner style and avoiding the need to explicitly configure promise chains.

The elevation attribute specifies the direction angle for the light source from the XY plane towards the Z-axis, in degrees. Note that the positive Z-axis points towards the viewer of the content.

The right shift (>>) operator returns a number or BigInt whose binary representation is the first operand shifted by the specified number of bits to the right. Excess bits shifted off to the right are discarded, and copies of the leftmost bit are shifted in from the left. This operation is also called "sign-propagating right shift" or "arithmetic right shift", because the sign of the resulting number is the same as the sign of the first operand.