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  A simple example of drawing bar chart with label using d3.js

D3.js is a very popular graph library to help developers draw various kind of charts using JavaScript in a webpage. It utilizes the SVG format supported by all major modern browsers and can help developers get rid of the old age of Flash or server side graph drawing libraries. In this post, we will introduce some simple examples of drawing bar chart with labels using D3.js.  First, let's see what will be the final look of the graph drawn. Below is the complete source code for this example....

   JAVASCIPT,D3,BAR CHART,LABEL,TUTORIAL     2020-05-16 23:25:40

  Install both 32 bit and 64 bit WAMP server

WAMP server is a platform tool for serving PHP applications on Windows. It includes a combination of Apache, MySQL and PHP service which can help developers test or run PHP applications with minimal setup. Sometimes one would first have a 32 bit version of WAMP installed and a few applications have been configured. But later s/he would mistakenly installed a 64 bit version of WAMP and somehow the 32 bit version configuration is overwritten. This causes a problem where the old applications config...

   PHP,WAMP,64 BIT,32 BIT,MULTIPLE VERSION     2017-03-18 01:14:21

  MySQL Index Merge Optimization Practices

In production environment databases, it is often seen that some SQL where conditions include: equal condition on a normal index + primary key range query + order by limit Although using a normal index would be more efficient, the system chooses to use index merge instead in some cases. This article explores such index merge situations. Index Merge Official Introduction   The Index Merge access method retrieves rows with multiple range scans and merges their results into one. Generall...

   INDEX MERGE,MYSQL,PRIMARY INDEX,SECONDARY INDEX     2024-09-10 04:52:26

  How to be jQuery-free?

jQuery is now the most famous JavaScript library. There are around 57.3% websites in the world using jQuery, i.e, 6 out of 10 websites are using jQuery. If we only consider those websites which use libraries, then the percentage is even higher which is 91.7%. Although jQuery is very popular, its size is still a headache to many websites maintainers. The uncompressed jQuery 2.0 has a size of 235KB, the size is 81KB after optimization.The jQuery 1.8.3 which supports IE 6/7/8 has a uncompressed si...

   jQuery,JavaScript,ECMAScript,CSS3     2013-05-13 11:53:20

  Why MySQL 8 drops support of query cache

Many of you may have heard or used MySQL's query cache, because it used to be a popular way to improve MySQL's performance. As an important feature for improving MySQL's performance, the query cache was often recommended as a solution for slow queries. However, why has MySQL 8 abandoned the query cache? Today, we will analyze and explore this decision. What is query cache? According to official document: The query cache stores the text of a SELECT statement together with the correspon...

   MYSQL 8,QUERY CACHE     2023-03-11 09:05:17

  How to check which Ohai plugin hangs in chef client run

Ohai plugins are very important components in chef client which aims to provide resource management automation on a server. The data discovered by Ohai plugins are describing the current state of the server and they will be used to maintain the server in a desired state. Each Ohai plugin discovers a specific pierce of information about the server such as cpu, memory, middleware etc. However, there are rare occasions(well I am a bit optimistic here) someone may find that the chef client...

   HOW TO,CHEF-CLIENT,OHAI,UPTIME,HANG     2017-12-24 22:09:59

  Make Magento 2 Faster: Five Quick tips

In this post, you will learn from Magento development company experts about speeding up the Magento 2. We hope these tips will help you in making Magento 2 faster than before. Magento 2 is a powerful platform. Once installed and with no customization it is a fully functional store. They even give you a well-designed, responsive storefront. However as you add products and your own content things will incrementally begin to slow down. To combat that there are some things you can do to increase spe...

   MAGENTO,MAGENTO TUTORIAL,MAGENTO DEVELOPMENT     2016-07-14 00:17:45

  How to use Chome dev tool to find event handler bound to an element

As a front end developer, there is frequent need to debug JS code and sometimes need to find out what event handler has been bound to a HTML element. In this post, we will show how to find out the click event handler bound to a HTML element, this same applies to other events as well. Nowadays, a web application is usually very complicated and there are lots of JS codes which makes it difficult to find out what click event handler has been bound to a HTML element, especially when the JS source co...

   JAVASCRIPT,CHROME,CHROME DEV TOOL,EVENT LISTENER     2019-08-17 22:14:36

  Tips to improve JavaScript efficiency

Writing JavaScript code is tedious and error prone. You not only need to implement the necessary functions, but also need to ensure cross browser compatibility. This often causes the low efficiency of JavaScript developers. Here we recommend 12 tips you can benefit from. 1. Remove array element by index If we want to remove one element in an array, we can use splice. function removeByIndex(arr, index) { arr.splice(index, 1); } test = new Array(); test[0] = ’Apple’; test[1] = &rsq...

   JavaScript,Tips,Array     2013-07-27 20:50:40

  jQuery to check whether checkbox is checked

In Vanilla JavaScript, the correct way of checking whether a checkbox is checked is to get the property checked of the checkbox. Assuming there is an checkbox with id "checkbox1", below line will return true if the checkbox is checked while it will return false if the checkbox is unchecked: document.getElementById("checkbox1").checked In jQuery, there are a few ways to check this. The first one is to using the corresponding counterpart of the Vanilla JavaScript, it is to check the checked proper...

   jQuery,checked,checkbox,attr,prop     2015-07-25 08:49:54