Every browser has a console reporting problems the page encountered: files that failed to load, scripts that errored, and requests that were blocked. Many of these are invisible visually, which is why a form can stop working while the page looks perfectly normal.
Opening it
Right-click anywhere on the page, choose Inspect, and select the Console tab. On most browsers the keyboard shortcut is F12.
That is the whole barrier. The panel looks technical and most of what it reports is readable English, and a substantial share of website problems are named in it directly.
What the colours mean
| Type | Meaning |
|---|---|
| Red, error | Something failed. Worth investigating. |
| Yellow, warning | Something is deprecated or suboptimal. Usually ignorable. |
| Plain, log | Informational output, often left in by a developer or a plugin. |
Only the red entries matter for most purposes, and even among those, some come from third-party scripts you do not control.
The errors that actually matter
404 on a file the page needs
A stylesheet, script, image, or font that could not be found. The most common genuine error and the easiest to fix, since the message names the file and the path it looked in.
Usually caused by a file renamed, moved, or deleted, or by a path that was correct on the old site and not the new one.
Uncaught reference or type errors
A script tried to use something that does not exist. This is what breaks interactive elements: a form that does not submit, a menu that does not open, a gallery that does not advance.
Frequently caused by two scripts conflicting, or by a script loading in the wrong order.
Mixed content blocked
The page is served securely and is requesting something insecurely, so the browser blocks it. Common after moving a site to HTTPS, and it silently removes images or scripts.
CORS errors
A request to another domain was refused. Usually a third-party service that is misconfigured or has changed its rules, and typically not something you can fix on your own site.
Why this matters more than it sounds
Because these failures are frequently invisible.
A script that errors part way through stops running, which means everything after it in that file does not happen. If your form validation and submission are in that file, the form silently stops working while looking entirely normal to a visitor.
That is the single most valuable use of the console for a small business: confirming that the enquiry form still functions after any change, in a way that looking at the page cannot.
The network tab, briefly
Next to the console and worth knowing about.
It lists every file the page requested, how large each was, and how long it took. That answers two questions quickly: what is making the page heavy, and whether something is failing that the console did not report.
Sorting by size usually identifies the oversized image responsible for a slow page in about ten seconds, which is faster than most speed tools.
What to ignore
- Warnings about deprecated features, which are notes for developers rather than faults.
- Errors from browser extensions, which appear on every site including ones that work perfectly. Checking in a private window without extensions separates these.
- Third-party analytics and chat script noise, which is common and rarely actionable.
- Anything on a page that works correctly. A console entry with no visible symptom is usually not worth a project.
Using it after a change
The practical habit: after any update, redesign, or plugin change, open the console on the homepage and one service page, and submit the contact form with the console open.
That takes two minutes and catches the class of failure that otherwise goes unnoticed for weeks, because nothing about the page indicates anything is wrong. It belongs alongside the checks in keeping software updated without breaking things.
What to send a developer
The exact text of the red error, the file and line number it names, the page it happened on, and what you were doing at the time.
That turns a report of the form not working into a specific starting point, and it frequently reduces a diagnostic session to a single fix. Screenshotting the console is enough; there is no need to interpret it.
Frequently asked questions
How do I open the browser console?
Right-click the page, choose Inspect, and select the Console tab. On most browsers F12 does the same thing.
What do the different console messages mean?
Red entries are errors where something failed, yellow are warnings that are usually ignorable, and plain entries are informational output left by a developer or plugin.
Which console errors actually matter?
Files returning 404 that the page needs, script errors that stop execution, mixed content blocked after moving to HTTPS, and refused requests to other domains.
Why would my form stop working with no visible sign?
A script that errors stops running, so everything after it in that file never happens. If form submission is in that file, it silently fails while the page looks normal.
What should I ignore in the console?
Deprecation warnings, errors from your own browser extensions, and third-party script noise. Checking in a private window without extensions separates your own problems from theirs.
What should I send to a developer?
The exact text of the red error, the file and line it names, the page it occurred on, and what you were doing. A screenshot is enough and there is no need to interpret it.
West Coast Media Solutions Inc. provides web design, web development, hosting, digital marketing, and business consulting to organisations across Canada, drawing on more than twenty-five years in the field.
Something on your site not working and no obvious reason?
We read what the console and network tab are already reporting, which usually names the fault in the first few minutes.
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