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  The war with spam comment

Spam comments are annoying and notorious. They are either malicious data from hackers to exploit the loopholes of the site or advertisements posted by robots. These kinds of comments have their own features and patterns, if we are careful enough, we can find ways to block most of them although it's not so easy. To block the comment with malicious executable codes such as JavaScript, we should remember one rule : never trust user input. So wherever there are user inputs, we need to check the vali...

   Spam comment,Block,Filter     2013-11-29 20:29:43

  Understand this in JavaScript

In JavaScript, this is always pointing to the owner of a function or a method. Function Let's check out function first. function introduce() {      alert("Hello, I am Laruence\r\n"); } For this function, what does this point to? In JavaScript, a global function's owner is the current page, i.e, the window object. Because its a method of the window object if we define a global function. Now you should know the this will point to the window object in the above function. ...

   JavaScript,this,event,call     2013-04-03 04:10:03

  The magic of go:linkname

When writing Go program, there is frequent need on using time.Sleep() function to pause the logic for some time. And if jumping to the definition of this function, can see below definition: // Sleep pauses the current goroutine for at least the duration d. // A negative or zero duration causes Sleep to return immediately. func Sleep(d Duration) I's strange that there is no function body defined here. What happened? The actual definition of the function body is residing at runtime/time.go&nb...

   TRICKS,GO:LINKNAME,GOLANG     2022-04-10 08:39:00

  Check whether a remote server port is open on Linux

As a system administrator or network engineer or application developer, there is a need to check whether a port on remote server is open so that you can tell whether the service under check is running or not. In this post, we would cover a few methods to check whether a remote server port is open or not on Linux. telnet telnet is the most frequently used command on both Windows and Linux to check port. The simple usage for this command is  telnet [host] [port] When the port is open, the o...

   LINUX,TELNET,PORT,NC,NMAP     2017-12-23 11:45:20

  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

  37 powerful Linux shell commands

To work on Linux platform, you cannot avoid using shell commands to complete some tasks. These tasks can be as simple as list files in some directories or find some text in some file, or can be as complex as monitoring processes. In this post, we will share 37 powerful Linux shell commands.   Task Commands 1 Delete file with 0 byte(empty file) find . -type f -size 0 -exec rm -rf {} \;find . type f -size 0 -delete 2 Check process memory consumption ps -e -o "%C : %p : %z : %a"|sort -k...

   Linux command,List     2013-09-16 07:47:16

  I don’t like the Ruby 1.9 hash syntax

There, I said it, I don’t like it. And I don’t know why you do either. I assume you like it anyway, everyone else I talk to seems to. My heart sank over and over again whilst I was at the recent RailsConf and saw respected rubyist after respected rubyist using the new Ruby 1.9 hash syntax in their presentations. I just don’t get it. But I’m not one to just moan. I plan to justify my feelings. Then maybe you can tell me why you do like it? My friend the hash rocket I ...

   Ruby,1.9,Hash,Feature     2011-12-14 07:05:09

  No support of $.browser in jQuery 1.9

Starting from jQuery 1.9, $.browser is no longer supported to detect the nrpwser type and version. The substitute is $.support. In the newer jQuery 2.x versions, IE 6/7/8 are also not supported. If users want to support IE 6/7/8, they must use jQuery 1.9. If you want to fully support IE and want to use jQuery 1.9 and jQuery 2.0, the official solution is: <!--[if lt IE 9]> <script src='jquery-1.9.0.js'></script> <![endif]--> <!--[if gte IE 9]> <script src=...

   jQuery,$.browser,$.browser.version     2013-08-27 03:10:12

  Popular Golang JSON libraries evaluation

JSON (Javascript Object Notation), a prevailing data exchange format, is widely used in various platforms and languages. Golang, of course, will never miss the support for JSON. And with its own standard library, such as those interfaces like the REST API from the API Service in Kubernetes, it can easily process JSON. Although Go’s library works great, we can still seek those open-source JSON libs in Github to maximize our efficiency. Then the features, performance, applicability of these ...

   FASTJSON,JSON LIB,JSON LIB COMPARISON,GO-JSON     2021-12-11 23:13:23

  A plugin to update last_error in Delayed Job

delayed_job is a process based asynchronous task processing gem which can be ran at background. It will fork the specified number of processes to execute the tasks asynchronously. The task status is usually stored in the database so that it can be easily integrated into a Rails application where asynchronous job execution is desired. Normally when a job fails to execute or error occurs, it would save the error into the database with the column last_error. Ideally all these will be handled b...

   RUBY,RUBY ON RAILS,DELAYED JOB,LAST_ERROR     2017-11-18 13:05:49

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