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  Name resolution order in JavaScript

To understand what value a variable has in JavaScript, we need to understand some concepts such as scope and name resolution order. JavaScript has two scopes; one is program level and the other one is function level. Unlike in C,C++ or Java, JavaScript has no block level scope. So a variable defined in a if block will still be available outside. For example, the below example: var foo = 1; function bar() { if (true) { var foo = 10; } alert(foo); } bar(); The alert will display 10 since the ...

   JavaScript,Scope,Name resolution     2013-07-10 01:29:28

  The craziest Javascript implementations

Since its birth in 1994, Javascript has come a long way. Today it’s one of the most popular programming languages on the web because of high popularity of AJAX based web-applications. Also the rise of micro-frameworks such as jQuery (also Prototype, Moo Tools etc) which have reduced dramatically the complexity of code developers needed to write, it is well tested, has a ton of plug-ins, has a large development community and reduced development time.And lately even Server-S...

   JavaScript,Crazy implementation,JVM,Turing machine     2012-01-03 12:09:42

  How to choose JavaScript template engine?

With the increase of density of web front end development, AJAX and JSON are used more and more frequently, it's necessary to use many tags in front end development. You may have a JSON object as below: var data={  email: 'terry.li@gbin1.com,  gender: 'male'  } Then you need to organize the JSON data into page elements. var email, gender;email= ' ' + data.email+ '; gender= ' ' + data.gender + '; $('#contentwrapper‘).append(content).append(gender); The output is very simple: ...

   JavaScript template engine,Template     2012-10-07 07:03:58

  Update parent window after closing the window opened by window.open()

Imagine we have a webpage which has a text field to let user enter a date. Usually, we may create a calendar window to ask the user to pick one date from the calendar window, when the date is picked, the calendar window will close and the date picked will be put into the text field. This way involves the window.open() method in JavaScript, and we may think how the opened window knows its parent window and then updates the parent window. I give a simple demo on this.We have two pages, on is the p...

   window.open, JavaScript,update, return value     2012-06-23 01:36:32

  Inspiring facts about JavaScript

JavaScript has been advocated as the first language to be learned by people who want to program. We have discussed the reasons why we should do so. Recently with the popularity of Node.js, JavaScript has become a full-stack language,  it can be used as both frontend and backend programming language. Today we will give some hard facts which will convince you about the popularity of JavaScript. Just like William Ting said ""JavaScript will stay relevant as long as people use the internet". Ye...

   JavaScript,popularity     2014-06-07 08:52:36

  A Javascript When Function

function when(conditionFunc, execFunc, interval){ if (conditionFunc()){ execFunc(); }else{ setTimeout(function(){ when(conditionFunc, execFunc, interval);}, interval); } } You have some code which should only execute when a condition is true. E.g. You have code which relies on a javascript library but can't be sure the library has loaded yet and don't want the code to execute until it has. This is common if you have a bookmarklet which injects more than one <...

   JavaScript,When,Implementation,When function     2012-02-24 05:08:34

  Tips and tricks about JavaScript from Google

JavaScript is now a very popular client side language. It's flexible, powerful but easy to make mistakes. So good programming style is better for you to write efficient and readable JavaScript codes. Here are some tips and tricks about JavaScript from Google. True and False Boolean Expressions The following are all false in boolean expressions: null undefined '' the empty string 0 the number But be careful, because these are all true: '0' the string [] the empty array {}&n...

   JavaScript, Google, Coding standard     2013-02-26 23:11:03

  Accurate floating point number calculation in JavaScript

In JavaScript, since floating point is defined with IEEE754,there will be some accuracy issues while doing floating point number arithmetic. Here is a function which can resolve the accuracy issue. var calc = function(num1,operator,num2,len){    var numFixs = function(num){        var arr = num.toFixed(len).toString().split('.');        return parseInt(arr.join(''));    }    switch(operator){...

   JavaScript, floating point,IEEE 754,accuracy     2012-12-27 11:07:49

  CSS Animation vs. JavaScript: Which One Is Better?

You know that there are two ways of creating animations on the web: with CSS and JavaScript. And, their selection completely depends on the dependencies of the project. But many web developers hold a wrong perception that CSS is the only way of creating the animations. In fact, CSS has established as the most pampered system of the web development industry and most of the developers recommend it because it is mobile-friendly and powerful system. No doubt CSS is good, but JavaScript is the best....

   CSS animation, JS animation     2015-07-24 02:45:01

  I’m too lazy to be a HTML developer

There’s no denying it. I’m just to damn lazy to be an HTML developer. This really sunk in when I looked at a tutorial for doing a jQuery Lightbox – for a client project. The tutorial was titled “Super Simple Lightbox with CSS and jQuery” but after reading it over I thought a better title would be “A really freaking hard tutorial on the inane intricacies of doing something that looks simple but in reality is a skein of HTML, Javascript and CSS that no...

   Web design,HTML,JavaScript,Complexity,Messy     2011-12-18 10:42:45