Iteration protocols aren't new built-ins or syntax, but protocols. These protocols can be implemented by any object by following some conventions.... js // Satisfies both the Iterator...generator object is an example: js const aGeneratorObject = (function*...
A lookahead assertion "looks ahead": it attempts to match the subsequent input with the given pattern, but it does not consume any of the input — if the match is successful, the current position in the input stays the same.... For example: js /(?=(a+))a*b\1/.exec("baabac");...always succeed. For example: js /(.*?)a(?!(a+)b\2c)\2(.*)/.exec("baaabaac");...
Many people need or want to interact with the web using multiple personas. They may have accounts for web-based work and personal email. They might sign out of their social media accounts before accessing online shopping, to ensure that any tracking scripts on the shopping sites can't pick up their social media activity. Users often use a standard and private browser window or two different browsers to address these requirements....js script writes the list of contextual...<script src="context.js"></script> </body> context.js All the extension's...
To provide quality support for touch-based user interfaces, touch events offer the ability to interpret finger (or stylus) activity on touch screens or trackpads.... js function startup() { const el...track of the touches in-progress. js const ongoingTouches = []; When...
The for...in statement iterates over all enumerable string properties of an object (ignoring properties keyed by symbols), including inherited enumerable properties.... Try it Syntax js for (variable in object) statement...property names and their values. js const obj = { a: 1, b: 2, c:...
The JavaScript exception "BigInt negative exponent" occurs when a BigInt is raised to the power of a negative BigInt value....a negative BigInt as exponent js const a = 1n; const b = -1n;...value, like 0n or undefined . js const a = 1n; const b = -1n;...
The JavaScript exception "invalid range in character class" occurs when a character class in a regular expression uses a range, but the start of the range is greater than the end.... Examples Invalid cases js /[2-1]/; // The range is out...95, = has value 61 Valid cases js /[1-2]/; // Swap the range /[_\-=]/;...
Learn about the HTMLInputElement.select() method, including its syntax, code examples, specifications, and browser compatibility.... Syntax js select() Parameters None. Return...ect text</button> JavaScript js function selectText() { const...
The JavaScript exception "is not a non-null object" occurs when an object is expected
somewhere and wasn't provided. null is not an object and won't work....number), will throw an error: js Object.defineProperty({}, "key"...object might look like this: js Object.defineProperty({}, "key"...