Firefox
1. Open the Console
Go to the screen where you are experiencing the error. In Firefox, navigate to Tools > Web Developer > Error Console or press Ctrl + Shift + J.
2. Identify the Error
The error console will open. If you don't see any errors try reloading the page. The error may be generated when the page loads.
The console will provide you with the error type, the location of the error and the line number
The image above shows the error to be in jquery.js on line 2.
Internet Explorer
Bear in mind, IE behaves vastly differently from other browsers when it comes to JS errors, and reports on them in disparate ways. The first thing to check when facing a problem in IE is if the problem only exists in IE. Also note that the debugging tools built into some IE versions are limited, and may not be available.
1. Open the Console
Go to the screen where you are experiencing the error. In Internet Explorer, navigate to Settings > F12 Developer Tools. Or click F12
Click on the Console tab.
2. Identify the Error
The error console will open. If you don't see any errors try reloading the page. The error may be generated when the page loads.
The console will provide you with the error type, the location of the error and the line number
The image above shows the error to be in jquery.js on line 2.
Chrome
1. Open the Console
Go to the screen where you are experiencing the error. In Chrome, navigate to View > Developer > JavaScript Console or More Tools > JavaScript Console or press Ctrl + Shift + J.
2. Identify the Error
The error console will open. If you don't see any errors try reloading the page. The error may be generated when the page loads.
The console will provide you with the error type, the location of the error and the line number
The image above shows the error to be in jquery.js on line 2.
Safari
1. Enable Developer Tools
Navigate to Safari > Preferences > Advanced and check the box that says Show Develop menu in menu bar
2. Open the Console
Go to the screen where you are experiencing the error. In Safari, navigate to Develop > Show Error Console
3. Identify the Error
The error console will open. If you don't see any errors try reloading the page.
The console show you the error, the error location and the line number:
The image above shows the error to be in jquery.js on line 2.
Note: If you cannot see the error click the back button within the console.
Opera
1. Open the Console
Go to the screen where you are experiencing the error. In Chrome, navigate to Tools > Advanced > Error Console.
2. Identify the Error
The error console will open. Select JavaScript and Errors from the two drop downs. To find the error location, expand one of the errors. You'll see the error and the location.
The image above shows the error to be in jquery.js on line 2, however remember to copy the whole stack information! Just saying what line is less helpful that showing context.