What Is Script Debugging?

by Sue Smith
Finding and fixing bugs is vital for reliable programs.

Finding and fixing bugs is vital for reliable programs.

When programmers write scripts, they rarely write them with no errors on the first attempt. Programming is a process of trial and error. Debugging is the act of finding and addressing errors in script code. These errors can be in the syntax used or in the logical structures within a piece of processing. Debugging is an essential skill for anyone developing either Web or desktop applications.


Programmers typically write a section of code then test it, so that they continue identifying errors and fixing them throughout the development process. However, even once a script is deployed, unforeseen errors may continue to arise. The debugging activity often recurs throughout the life-cycle of a project, from the development to the testing phase. To debug code, developers first need to figure out the source of each error, then make amendments to the code to resolve it.


Programming code can contain different types of error developers look for when debugging. Syntax errors are mistakes in the code structures, resulting in statements that are not valid within the language in use. With some technologies, developers use Integrated Development Environments to write their code. In an IDE, the programmer is alerted to syntax errors in their code, making it easier to locate and fix these errors at an early stage. Syntax errors are like grammatical or typing mistakes in natural language.


While syntax errors are often identified at the initial development stage of a scripting project, semantic errors often go unnoticed until a later phase. A semantic error is a mistake in the logic of a script. Programming code implements logical algorithms, or processes, within various structures such as loops and conditional tests. If a programmer fails to translate the desired process into programming code correctly, this is a semantic error. Some semantic errors can cause scripts to crash, but many more produce unpredictable behavior that may be less visible.


Debugging can take place during both the development and testing phases, with different types of error most likely to crop up at different stages. Syntax errors tend to be identified at earlier stages, with semantic errors often being picked up only after extensive testing. When developers make alterations to address errors during debugging, they then need to test the scripts over again in case their changes have any unpredictable effects. For Web development, programmers can install browser extensions to aid the debugging process.

About the Author

Sue Smith started writing in 2000. She has produced tutorials for companies including Apex Computer Training Software and articles on computing topics for various websites. Smith has a Master of Arts in English language and literature, as well as a Master of Science in information technology, both from the University of Glasgow.

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