[{"data":1,"prerenderedAt":60},["ShallowReactive",2],{"\u002Fglossary\u002Flong-task":3,"\u002Fglossary\u002Flong-task:related":43},{"id":4,"title":5,"author":6,"authorImage":7,"body":8,"category":28,"date":29,"description":30,"draft":31,"extension":32,"letter":33,"meta":34,"navigation":35,"path":36,"readTime":37,"related":38,"seo":39,"stem":41,"term":5,"__hash__":42},"glossary\u002Fglossary\u002Flong-task.md","Long Task","Fabian Krumbholz","\u002Fimages\u002Fauthors\u002Ffabian-krumbholz.webp",{"type":9,"value":10,"toc":24},"minimark",[11],[12,13,14,15,19,20,23],"p",{},"A long task is any piece of JavaScript code that monopolizes the ",[16,17,18],"strong",{},"Main Thread"," for a prolonged period (typically over 50 milliseconds), preventing it from responding to user input. While a long task is running, the browser cannot react to clicks or taps, making the page feel frozen and unresponsive. Long tasks are a primary cause of a poor ",[16,21,22],{},"Interaction to Next Paint (INP)"," score. The most effective way to optimize them is to break them into a series of smaller tasks, yielding control back to the main thread between each one.",{"title":25,"searchDepth":26,"depth":26,"links":27},"",2,[],null,"April 8, 2026","A long task is any piece of JavaScript code that monopolizes the Main Thread for a prolonged period (typically over 50 milliseconds), preventing it from responding to user input.",false,"md","L",{},true,"\u002Fglossary\u002Flong-task","1 min read",[],{"title":40,"description":30},"Long Task: Definition | Web Performance Glossary","glossary\u002Flong-task","9ZAWM6vRUEfg1S16cZvIJ6OAYc2OwLL9lfgiFu_5BL8",[44,48,52,56],{"path":45,"title":46,"description":47,"letter":33},"\u002Fglossary\u002Flab-data-synthetic-monitoring","Lab Data (Synthetic Monitoring)","Lab data is performance data collected in a controlled, repeatable environment using tools like Google Lighthouse or WebPageTest.",{"path":49,"title":50,"description":51,"letter":33},"\u002Fglossary\u002Flargest-contentful-paint-lcp","Largest Contentful Paint (LCP)","A Core Web Vital that measures the perceived loading speed of a page. It marks the point in time when the largest content element (usually a hero image or a large block of text) becomes visible within the viewport.",{"path":53,"title":54,"description":55,"letter":33},"\u002Fglossary\u002Flargest-contentful-paint-subparts","Largest Contentful Paint Subparts","The LCP Subparts are the distinct phases that make up the total Largest Contentful Paint time. Analyzing this breakdown is crucial for diagnosing the root cause of a slow LCP.",{"path":57,"title":58,"description":59,"letter":33},"\u002Fglossary\u002Flayout-thrashing","Layout Thrashing","Layout Thrashing is a harmful performance anti-pattern.",1787756715022]