performance

 Performance  typically refers to the speed, responsiveness, and initial load of a website; performance may also refer to the post type, performance. Poor silo performance can be a motivation for setting up, using, publishing to your own website.

Badly written Javascript, particularly poor use of frameworks, can cause bad site performance, perhaps an example of:



Tools

 * Google PageSpeed Insights
 * webpagetest.org can give you some ideas how and what to optimize
 * thinkwithgoogle.com analyse your website for mobile/desktop with scoring and recommendations to fix issues based on different criteria of importance to get a better scoring.