$(selector)

Shorthand for document.querySelector.

$$(selector)

Shorthand for document.querySelectorAll.

$x(xpath)

Returns an array of elements that match the given XPath expression.

$0

Represents the currently selected node in the content browser.

$1..4

Represents the last, second to last, third to last, and fourth to last selected node in the content browser, respectively.

$_

Returns the value of the last evaluated expression.

dir(object)

Prints all the properties of the object.

dirxml(object)

Prints all the properties of the object. If the object is a node, prints the node and all child nodes.

keys(object)

Prints an array of the names of the object’s own properties.

values(object)

Prints an array of the values of the object’s own properties.

profile([title])

Starts the Javascript profiler. The optional argument title contains the string to be printed in the header of the profile report. See Javascript and Events Recording.

profileEnd()

Stops the Javascript profiler and prints its report. See Javascript and Events Recording.

getEventListeners(object)

Prints an object containing the object’s attached event listeners.

monitorEvents(object[, types])

Starts logging all events dispatched to the given object. The optional argument types defines specific events or event types to log, such as “click”.

unmonitorEvents(object[, types])

Stops logging for all events dispatched to the given object. The optional argument types defines specific events or event types to stop logging, such as “click”.

inspect(object)

Inspects the given object; this is the same as clicking the Inspect button.

copy(object)

Copies the given object to the clipboard.

clear()

Clears the console.

console.assert(expression, object)

Asserts whether the given expression is true. If the assertion fails, prints the error and increments the number of errors in the activity viewer. If the assertion succeeds, prints nothing.

console.clear()

Clears the console.

console.count([title])

Prints the number of times this line has been called.

console.debug(object)

Alias of console.log().

console.dir(object)

Prints the properties and values of the object.

console.dirxml(node)

Prints the DOM tree of an HTML or XML node.

console.error(object)

Prints a message to the console with the error icon. Increments the number of errors shown in the activity viewer.

console.group([title])

Prints subsequent logs under a disclosure of the given title.

console.groupEnd()

Ends the previously declared console grouping.

console.info(object)

Alias of console.log().

console.log(object)

Prints the object to the console with the log icon. Increments the number of logs shown in the activity viewer.

console.markTimeline(label)

Marks the Timeline with a green vertical dashed line that indicates when this line of code was called. See Recording Timelines.

console.profile([title])

Starts the Javascript profiler. The optional argument title contains the string to be printed in the header of the profile report. See Javascript and Events Recording.

console.profileEnd([title])

Stops the Javascript profiler and prints its report. See Javascript and Events Recording.

console.time(name)

Starts a timer associated with the given name. Useful for timing the duration of segments of code.

console.timeEnd(name)

Stops the timer associated with the given name and prints the elapsed time to the console.

console.trace()

Prints a stack trace at the moment the function is called. See Figure 4-2.

console.warn(object)

Prints a message to the console with the warning icon. Increments the number of warnings shown in the activity viewer.

debugger

Stops Javascript execution at the current line. This is the equivalent of setting a breakpoint programmatically. See Breakpoints.