How to optimize web page loading? From theory to practice

at the peak of traffic dividends, web page loading speed has become the core factor affecting user retention and search engine ranking. According to statistics, more than 50% of users will give up web pages that take more than 3 seconds to load, and optimizing web page loading can not only reduce bounce rate, but also improve conversion rate and brand likability. This article will disassemble and optimize the landing path of web page loading in an all-round way from basic cognition, practical methods to effect verification, and help you turn theory into executable solutions to achieve qualitative improvement in web page performance.

, optimize the page loading first clear the core indicators?

want to accurately optimize web page loading, you must first know what indicators to measure the effect, to avoid blind adjustment.

1, maximum content drawing LCP

LCP is the core indicator to measure the loading experience of web pages, which refers to the time from the start of loading to the completion of the largest visible element rendering. The optimal standard is less than 2.5 seconds. When optimizing web page loading, focus on the core content in the following tabs, such as the first screen large image, title text, etc., to ensure that such resources can be loaded first, so as to shorten the LCP time.

2, first input delay FID

FID measures the time it takes for the user to interact with the web page for the first time to respond to the browser, reflecting the interaction fluency of the web page. When optimizing the loading of the web page, it is necessary to reduce the size of the JavaScript file loaded on the first screen, avoid the main thread being occupied for a long time, and allow users to quickly trigger buttons, text boxes and other interactive operations. The optimal standard for FID is within 100 milliseconds.

Second, optimize web page loading from resource compression to landing?

resources such as pictures, videos, and codes in web pages are the main culprits that slow down the loading speed. By compressing the volume of resources, the goal of optimizing web page loading can be directly achieved.

1, image resources intelligent compression

images usually account for more than 60% of the total resource volume of web pages. The first step to optimize web page loading is to deal with pictures. Preference is given to using modern picture formats such as WebP and AVIF, which can compress the volume by 30% -50% while ensuring image quality; at the same time, according to the screen definition of different devices, provide suitable picture sizes to avoid mobile end loading high definition large pictures on the desktop. Lazy loading technology can also be used to allow non-first screen pictures to be loaded when the user scrolls to the corresponding area.

2, code file compression and merging

compress HTML, CSS, JavaScript files, remove comments, spaces and other redundant content, which can effectively reduce the file size. At the same time, merge multiple small files of the same type into one to reduce the number of HTTP requests, such as merging multiple CSS files into a style.css, reducing the time cost of server response, which is also a key operation to optimize web page loading.

3. Optimize web page loading Need to optimize code execution logic?

in addition to resource compression, the execution logic of the code will also affect the loading efficiency. Reasonable adjustment of the code loading order can further optimize the loading effect of the webpage.

1, non-core code lazy loading

set the JavaScript code that does not affect the first screen rendering, such as statistical scripts, advertising plug-ins, etc., to lazy loading, and then execute it after the first screen content is loaded. You can use async or defer attributes to mark such scripts to avoid them blocking the HTML parsing process, allowing users to see the first screen content faster, and helping to optimize the landing of web page loading.

2, using CSS internal connection and critical path optimization

the CSS code internal connection necessary for first-screen rendering to the HTML header to avoid the browser's delay in rendering due to waiting for external CSS files. At the same time, optimize the critical rendering path to reduce the loading and parsing time of HTML, CSS, and JavaScript files, so that the browser can build a rendering tree at the fastest speed and complete the drawing of the first-screen content. This is also an important part of optimizing web page loading.

4. Optimize web page loading to configure a reasonable caching strategy?

cache allows repeated users to load resources directly from the local without having to request the server again, which is an effective means to optimize web page loading for a long time.

1, browser cache static resource

set the cache expiration time for static resources such as pictures, CSS, and JavaScript by setting the Cache-Control and Expires fields in the HTTP response header. For example, the cache time of pictures is set to 30 days. After the user visits for the first time, the resources will be loaded directly from the local cache when they visit again within 30 days, which greatly shortens the loading time and continuously optimizes the user experience of web page loading.

2, using CDN to distribute static resources

CDN is the information delivery network, which can distribute static resources to multiple node servers around the world. When users visit, they will obtain resources from the closest node and reduce the delay of network transmission. After configuring the CDN, it can not only improve the loading speed of resources, but also reduce the pressure on the source server. It is also of great help to optimize the stability of web page loading.

To sum up, optimizing web page loading is a systematic project, which needs to be promoted in multiple dimensions from core index cognition, resource compression, code logic optimization to cache strategy configuration. First, the optimization direction is clarified through LCP, FID and other indicators, and then the actual operation such as picture compression and code streamlining is implemented. Finally, cooperate with the cache strategy to consolidate the optimization effect. As long as you follow this path, you can effectively improve the loading speed of web pages, bring a smoother access experience to users, and help websites get better rankings in search engines.