Diagnosing in the browser.
WHAT THEY PROVIDE
Inspecting the document and applied styles The console, showing errors and allowing evaluation Network activity for every request Performance recording Storage inspection Device simulation
WHAT TO USE THE INSPECTOR FOR
Establishing which style rule applied and why Testing changes live Examining the structure as the browser sees it
WHAT TO USE THE CONSOLE FOR
Reading errors, which state the file and line Evaluating expressions Inspecting values
WHAT TO USE THE NETWORK PANEL FOR
What was requested The status of each The size and timing What is slow, and what is large
WHAT THAT REVEALS
Requests failing silently Assets far larger than expected Requests nobody intended
WHAT TO USE PERFORMANCE RECORDING FOR
Where time is spent, rather than guessing.
WHAT TO CHECK IN STORAGE
What is stored, including anything that should not be.
WHAT TO ALWAYS DO WITH AN ERROR
Read it. It usually states the file, the line and the cause.
