There are many errors that can occur in a system. JavaScript provides a message for all the errors at run time and dynamically generate the error code. The errors that are present :

Load-time errors :

These are the errors that come when loading a web page like using of improper syntax and the errors gets detected the moment user loads a page.

Run-time errors :

These are the errors that comes due to misuse of the language commands used inside the HTML document. This shows that it has loaded but the functionality is not properly integrated.

Logic errors :

These are the errors that comes due to bad logic performed on a function that is having different operation but it is made to have logic differently.