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, but written as a separate JS file is conducive to the separation of structure and behavior.4, cross-platform features, under the support of most browsers, can be run on a variety of platforms (such as Windows, Linux, Mac, Android, iOS, etc.)
Basic syntax (variables, expressions, scopes, various keywords, and process Control statements)Cond...What is the
Java brother, at least in the appearance of dress up, inside still have to flow my old net blood. ”
One sentence summary: Java and JavaScript are two different languages.
1 Language Features:
1.1 Weak type:
JavaScript does not strictly distinguish between data types when declaring variables (var variable name), not as strict as Java (type: variable name). Also say,
insights.
After reading it, it seems that there are very few gains. Today, I have time and painstaking efforts to write down my post feelings and start with my actual actions.The "digital recording of all kinds of things that are worth sharing with you, what you think, what you read" Program (more fragmented sharing, you are welcome to follow my Twitter: @ turingbook and another person's @ Liujiang -- do
fnref = Outerfn () ; Fnref (); Instead of modifying global variables inside OUTERFN, a reference to INNERFN is returned from OUTERFN. This reference can be obtained by calling OUTERFN, and the reference may be saved in the variable.The fact that it is possible to invoke an intrinsic function by reference even if it leaves the scope of the function means that Java
(); fnref ();
The global variable is not modified in outerfn, but a reference to innerfn is returned from outerfn. You can obtain this reference by calling outerfn, and the reference can be saved in the variable.
The fact that, even if the function scope is left, the internal function can still be called by referencing, meansAs long as the call to internal
With JavaScript for more than a year, closures always let a person two Zhang Monk can't touch the head. Lu continued to contact the knowledge of some closures, also committed several times because do not understand the closure caused by errors, more than a year the information also looked at some, but still not very clear, recently accidentally looked at the appendix of the basic jquery tutorial, found in Appendix A on the introduction of
.) may be familiar with this.
But why does it frequently cause us a lot of trouble in JavaScript?
Let's start by saying that he's different from other programming languages.
In JavaScript, this is a special object that is not a value stored in an instance, as in other programming languages, and directly points to th
I have a headache this evening. Why?
After all, it's just half the way out. My Understanding of javascript only stays at: calling javascript, changing page styles, elements, and implementing responses to some events. Although it may be used when necessary, but the principle of use is not very clear, as for DOM, such a professional word, it
reference may be saved in the variable.The fact that it is possible to invoke an intrinsic function by reference even if it leaves the scope of the function means that JavaScript needs to preserve the referenced function as long as there is the possibility of invoking the intrinsic function. and the JavaScript runtime
First, the incidentAn event is a specific interaction moment that occurs in a document or in a browser window.An event is an action performed by the user or the browser itself, such as Click,load and MouseOver, which are the names of the events.Events are a bridge between JavaScript and the DOM.If you trigger, I execute--the event occurs, and the handler function
code (JS compiler will be the variable declaration to promote processing ).After understanding the concept of ascension, go back to the beginning of the understanding of code snippet 3, code snippet 3 and the code after being hositing as shown:The output structure is undefined! can be understood as an internal variable myvar in the last line of the anonymous function to declare the variable and assign a value, but the JS interpreter will declare the
What is the "closure" of JavaScript? (2)The title of my previous blog is incorrect, causing some misunderstandings. I think the purpose of a blog is not to back up textbooks, but to share the R D experience. The title of my previous article should be changed to "an issue of
can be matched, but not cross-row. in single-row mode, Perl pretends to treat multi-row strings as one line, and regards linefeeds as intra-row characters, so ". and match them. More vividly, it is to put the following three lines of text
123
As a line of text "1 \ n2 \ n3 \ n", this is what the single line mode means.
However, for the same reason (string variab
A conceptual explanation:undefined is one of the five original classes defined in the JavaScript language, in other words, undefined is not a program error, but a value allowed by the program. not defined is a bug that JavaScript bursts when it runs our
have any connection.Because the capture is X's reference, so the above three functions see X is the same variable.This is important because the local variables in JavaScript are not all in the heap . At least GOOGLE V2 is not. But the x above line 3 must be "Born and liv
What is a JavaScript closure?
This article is reproduced from: Zhongcheng translationTranslator: McbaiLinks: http://www.zcfy.cc/article/4639Original: https://medium.freecodecamp.org/whats-a-javascript-closure-in-plain-english-please-6a1fc1d2ff1c
The JavaScript programming language is developed by Netscape,inc., which is not part of the Java platform. JavaScript does not create small applications or standalone applications. In the most common form, JavaScript resides in HTML documents, providing a variety of web page
Label:The following reproduced from-Bird's nest-technology sharing community HTTP://T.RUNOOB.COM/QUESTION/13 (invasion of the deletion) 1, HTML, CSS, JavaScript front-end learning trilogy, according to this order to learn HTML tutorial, CSS Tutorial, JavaScript tutorial is right. For JavaScript, do the following two po
this internal function. Until the last variable is discarded, the JavaScript Garbage Collector can release the corresponding memory space (the red part is the key to understanding the closure ).
After talking about the closure for a long time, it is related to the closure. The closure refers to a function with the per
JavaScript-What is the variable object for this JS code?
alert (x); "X" is not Definedalert (b); "Undefinedx = 10;var y = 20;
Does x become a property of window rather than a variable? y is a variable object?
' Cause I saw this conversation.
In the
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