PerformancePaintTiming
The PerformancePaintTiming
interface of the Paint Timing API provides timing information about "paint" (also called "render") operations during web page construction. "Paint" refers to conversion of the render tree to on-screen pixels.
An application can register a PerformanceObserver
for "paint
" performance entry types
and the observer can retrieve the times that paint events occur. Use this information to help identify areas that take too long to provide a good user experience.
Properties
This interface has no properties but it extends the following PerformanceEntry
properties (for "paint
" performance entry types
) by qualifying and constraining the properties as follows:
PerformanceEntry.entryType
-
Returns "
paint
". PerformanceEntry.name
-
Returns either
"first-paint"
or"first-contentful-paint"
. PerformanceEntry.startTime
-
Returns the
timestamp
when the paint occurred. PerformanceEntry.duration
-
Returns 0.
Methods
This interface has no methods.
Example
function showPaintTimings() {
if (window.performance) {
let performance = window.performance;
let performanceEntries = performance.getEntriesByType('paint');
performanceEntries.forEach( (performanceEntry, i, entries) => {
console.log("The time to " + performanceEntry.name + " was " + performanceEntry.startTime + " milliseconds.");
});
} else {
console.log('Performance timing isn\'t supported.');
}
}
The code above produces console output something like the following:
The time to first-paint was 2785.915 milliseconds.
The time to first-contentful-paint was 2787.460 milliseconds.
Specifications
Specification |
---|
Paint Timing 1 # sec-PerformancePaintTiming |
Browser compatibility
BCD tables only load in the browser