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April 6, 2020
javascript debugging

Introduction To JavaScript Debugging

In this tutorial we will be looking at JavaScript debugging which entails how to debug JavaScript codes when finding and fixing bugs. In our previous tutorial we discussed about JavaScript animations and we explained how to create simple animations using functions in JavaScript. If you haven’t gone through the tutorial you can do so using the link below

Read previous tutorial on: JAVASCRIPT ANIMATION | How to Add Animation with JavaScript

JAVASCRIPT DEBUGGING

Bugs in JavaScript are also known as errors. Since errors are inevitable, developers tend to come across lots of errors when coding web pages or building software’s. Debugging has to do with finding and fixing errors present in the JavaScript codes and this process is also part of the web development process.

JAVASCRIPT DEBUGGING METHODS

Some of the ways you can debug a script include:

  • using a JavaScript validator
  • using a JavaScript debugger
  • Adding debugging code to your program

USING A JAVASCRIPT VALIDATOR

javascript validators or parser are very helpful programs used in checking JavaScript codes to ensure they are compliant with the right syntax. This program runs through the code to ensure they are in the right format and placement. You can find this program built into some of the latest HTML and JavaScript editors.

One of the JavaScript editors highly recommended for script validation is Douglas Crockford’s JavaScript Lint, and its available at Douglas Crockford’s JavaScript Lint.

USING JAVASCRIPT DEBUGGER

A javascript debugger is an application program that enables the programmer or developer run checks on all aspect of the script. This program places the script execution on the programmer and goes through the script one line at a time. The application tends to halt at points on the script that are suspected to need more attention. So the programmer checks this areas of the script for any fix or correction.

ADDING DEBUGGING CODE TO THE PROGRAM

Another method used in checking for bugs is with the use of debugging codes. We can easily add codes such as the alert() and document.write() methods to the program to alert us on any bugs found in the program.

var debug = true;
var TheImage = "widget";

if( debug )
   alert( "Calls swappingImage() with argument: " + TheImage );
   var swapStatus = swappingImage( TheImage );

if( debugging )
   alert( "Exits swappingImage() with swapStatus=" + swapStatus );

HOW TO REDUCE ERRORS WHEN CODING

The below steps will guide developers on error reduction when coding in JavaScript or any programming language;

  • Avoid writing long script of codes without double checking if they are correct.
  • Always use meaningful comments at all time to remind yourself why you wrote a line of code.
  • Maintain high consistence in your variable naming.
  • Be mindful of your quotation marks and and equal signs.
  • Always remember to declare your variables before using them.

NEXT TUTORIAL: JAVASCRIPT BROWSER COMPATIBILITY

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