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  An easy way to log client side information to server


JavaScript debug is a very troublesome thing in web application development. Because many web browsers will not notify you if there is any error in the JavaScript codes you write. They just silently fail and block the following codes execution. In order to debug JavaScript codes, we need a good log mechanism which will help us log the error information,, we often need to log errors in JavaScript codes to server for debug purpose in a production web application, What should we do? The first ...

   JavaScript log, Ajax,Image,Debug     2012-12-30 09:16:50


  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


  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


  JSON in JavaScript


When sending an AJAX request to the server, the response can have two formats : XMLHttpRequest.responseXML to access data with XML format and XMLHttpRequest.responseText to access data with string format. XML is the standard data transfer format, but one weakness is it's troublesome to parse and retrieve the data. JSON(JavaScript Object Notation) is a light weight data interchange format, we call it the JavaScript object representation. The advantage of using JSON as the data format is itself is...

   JSON,JavaScript     2013-05-04 23:25:57


  JavaScript: Passing by Value or by Reference


In JavaScript, we have functions and we have arguments that we pass into those functions. But how JavaScript handles what you’re passing in is not always clear. When you start getting into object-oriented development, you may find yourself perplexed over why you have access to values sometimes but not other times. When passing in a primitive type variable like a string or a number, the value is passed in by value. This means that any changes to that variable while in the function are complete...

   JavaScript,Function,Pass by reference,Pa     2011-07-28 11:05:25


  JavaScript Is Not A Language


Recently people presented arguments for and against using CoffeeScript. I felt the argument against was pointless and obviously wrong, but I couldn't figure out why, and I thought the counterargument for was kind of toothless and irrelevant. I've figured out the real issue.The real argument for CoffeeScript is that JavaScript is not really a language.Years ago I read something which explained, in my opinion, why Lisp has never achieved the mainstream adoption its passionate advocates belie...

   JavaScript,Not a language,CoffeeScript,Model     2011-12-29 08:46:15


  Ways to check existence of JavaScript object


The design of JavaScript is not so sophisticated. It's very easy for us to make mistakes if we are not very careful when using JavaScript. For example, to check the existence of JavaScript object.Now we want to check whether a global object myObj exists or not, if it doesn't exist, we declare it. The pseudo code for this is :    if(myObj not exist){        declare myObj;    }You may think it's very easy to write the code. In fact, ...

   JavaScript,object,existence     2012-05-03 08:40:04


  JavaScript showModalDialog method


In JavaScript, showModalDialog()  method creates a simple modal dialog box which is a simple html page but when a modal dialog opens, user can't switch to another page until it closes the modal dialog box. Syntax:  window.showModalDialog( url, arguments, feature options); Where url is the URL of page which is to be opened in modal window and arguments are those arguments which we are passing to the modal window and feature options are the attributes set for the modal windo...

   JavaScript,JS,showModalDialog,Example     2011-07-27 10:51:47


  7 Resources Every JavaScript Developer Should Know


A web developer today is expected to be an expert in every aspect of their craft and JavaScript is no exception.  Years ago JavaScript seemed to be more of an annoyance, producing those trailers at the bottom of the browser.  This has changed and JavaScript is a first-class citizen as a functional programming language and what seems like an unlimited number of resources covering the language. I have been doing more and more JavaScript lately, both on the front-end and some node.js...

   JavaScript,Resource,Study,Website     2012-03-15 12:54:40


  Solution to IE setAttribute style problem


In IE7, the JavaScript setAttribute("style","attributes") doesn't work, but it works in IE 8 and other web  browsers. To solve the STYLE problem in IE 7 we can use a workaround method.we can use element.style.cssText = 'color:#FF0000;';in IE 7 instead ofelement.setAttribute('style','color:#FF0000;'); ...

   JavaScript,Style,setAttribute, IE,Not work,Solution     2011-11-21 12:00:27