Browser based monitoring types, such as Full Page Checks, load your page(s) in an actual browser. The result of that is, in most cases, a waterfall chart which lists all of the elements and resources that were loaded as part of the page.
The elements that are loaded in the browser include first-party content, such as the original HTML document or images hosted in the same network, but can also include third-party content, such as external monitoring scripts or analytics. Each of these elements will be a separate entry in the waterfall chart, with its own request URL and load time metrics, as outlined in the waterfall chart article.
The Check URLs loaded by the page error condition allows a monitor to check whether or not any elements in the waterfall chart have a certain request URL. For example, a browser based monitor can be configured to confirm that Uptrends' Real User Monitoring is running on a page by checking whether the request URL of any of the waterfall elements matches hit.uptrends.com.
Configuring a waterfall element request URL check
To configure the ‘Check URLs loaded by the page’ error condition:
- Navigate to the monitor settings of the monitor in question. Either click its name in the list of monitors accessible via in the menu, or click ‘Edit’ in the quickinfo panel that appears when you hover over the monitor’s name.
- Open the Error conditions tab.
- Click the + New check button under Check URLs loaded by the page.
- Select whether the monitor should return an error when the specified URL does or does not appear as the request URL in any of the waterfall chart entries.
- Enter the (partial) URL. The entered value can be a regular expression.
- Click in the bottom left to save the monitor.
The following example shows the error condition checking whether the Uptrends RUM script has been correctly implemented, by confirming that hit.uptrends.com/.* (note the regular expression) is in the list of loaded elements. If this particular URL is not in the list of loaded elements, the monitor will generate an error.