Errata

"It’s an API (Application Programming Interface) that for working with structured documents such as XML, XHTML and HTML." This needs either a verb in the "that" clause, or "that" could just be deleted.

"It’s a collection of properties and methods that deal with browser’s specifics...." That should either be "browsers'" (apostrophe after the 's'), or have an article before it, "a browser's" or "the browser's".

"...so you can familiarize with it...." Needs "yourself" in there.

"It’s a very popular language, it is practically everywhere...." Comma splice; use a semicolon or full stop there.

((("environment" should be removed

"You can make alias to it in /bin/jsc...." "an alias", and I would change "in" to "at" to boot.

"You saw the first three of the first three of the five primitive types...." Looks like "three of the" got duplicated.

"Have you noticed ... used so far." It's a question, so that should end with a question mark.

"...that all code example..." "examples", plural

"Three equal signs mean _strict comparison...." There was probably supposed to be another underscore after "comparison", to make it italic, in parallel with the "loose comparison" in the following paragraph/bullet.

"...they'll always be casted to true...." This may differ for jargon use of "cast", but I've never seen a past or participle "casted"; it's always been uninflected.

"If you skip it will still work...." Needs "it" twice there, maybe with a comma in between.

"The $... is uncommon but absolutely valid part of a name." Should have either "an uncommon" or "a valid", depending on whether "uncommon" is meant to be a predicate adjective, or adjective describing "part".

In the interpreter's "comments" finding global_ten, "yey me!", I would really expect "yay".

"You’ve already seen the use of object literals at several occasions in this book. For example when talking about representing PHP’s associative arrays in JavaScript." Sentence fragment. Change period to comma, and lc "For".

"...the space around the dot in optional and the interpreter think you're trying...." s/in/is/, s/think/thinks/

"(strings literals can be converted...." s/strings/string/ or delete "literals"

"show up if you don’t filtered them out...." s/filtered/filter/

"...for any of the two objects." s/any/either/

"...in its 9 main constructor functions. Either as properties and methods...." Another sentence fragment; again, replace period with comma, and lc "Either".

"...when typeof in not enough." s/in/is/

"...the method hasOwnProperty(), it lets you differentiate...." Comma splice; replace the comma with a semicolon or period, and capitalize accordingly.

"...the last elements becomes the first and so on...." Either "elements become" or, even better, "element becomes", but one 's' or another has to go.

"Let's consider regular expressions next" missing period at the end of sentence & paragraph

"exec() ======" I think maybe you use three equal signs to indicate a header level, like in MediaWiki markup? And then somehow all six ended up following 'exec()', instead of three on each side. Otherwise, I don't know what's going on here.

Note from the Author or Editor:
yeah, mistake in formatting. I'm using AsciiDoc and lovin' it :) http://blog.stoyanstefanov.com/asciidoc/ http://www.jspatterns.com/unit-testing-in-asciidoc/

"Let's see an example is more detail." s/is/in/

"Both methods are the same in you don’t...." Should be "in that you don't".

"...equivalent of is_array() is PHP." Should be "in PHP."

"...or using it’s call method:" It's "its", not "it's". I.e. use "its" here.

"Attempt... will now be unsuccessful:" Should probably be either "An attempt" or "Attempting".

"Then this function return a new function...." "returns", of course

"...it would be wise to implements them...." "to implement"

"This chunks of code...." Probably "These chunks", maybe "This chunk".

"(say, on open source library)" "an" instead of "on"

"• adding all you stuff there" "your stuff"

"For a desert,..." Definitely "dessert", and I would say "For dessert," without an article.

"And we want to get the exact same object every time we call a specific constructor, We’ll looking for something that behaves like this:" * replace comma with period or question mark * "We're looking" or "We'll be looking" * might be better to recast this part altogether, with the preceding rhetorical question in mind

"...lets you to defer...." "lets you defer" or maybe "allows you to defer"

"...its great manual (http://php.net) especially with all the... comments." Could use a comma after the parenthetical.

"...you’ll happy to learn...." "you'll be happy"

"...may not be able deduct the purpose...." "able to deduce" (both missing 'to' and s/deduct/deduce/)

"...so the it provides...." Probably just remove 'the'. Alternatively, replace 'it' with an appropriate common noun.

"...some error are easily masked...." (oh, the irony!) s/error/errors/