Performance optimization for JavaScript: loading and execution
With the continuous promotion of Web2.0 technology, more and more applications use JavaScript technology for processing on the client side, making the performance of JavaScript in the browser the most important usability issue faced by developers. This problem is complicated by the blocking nature of JavaScript, which means that when the browser is executing JavaScript code, it cannot do anything else at the same time.
This article details how to correctly load and execute JavaScript code to improve its performance in the browser.
01-
Overview
No matter whether the current JavaScript code is embedded or in an external link file, the downloading and rendering of the page must stop and wait for the script execution to complete. The longer the JavaScript execution process takes, the longer the browser waits to respond to user input. The reason why browsers block when downloading and executing scripts is that the script may change the namespace of the page or JavaScript, which affects the content of subsequent pages. A typical example is using document.write() on the page. For example, Listing 1
Listing 1 JavaScript code inline example
<html> <head> <title>Source Example</title> </head> <body> <p> <script type="text/javascript"> document.write("Today is " + (new Date()).toDateString()); </script> </p> </body> </html>
When the browser encounters the

Hot AI Tools

Undresser.AI Undress
AI-powered app for creating realistic nude photos

AI Clothes Remover
Online AI tool for removing clothes from photos.

Undress AI Tool
Undress images for free

Clothoff.io
AI clothes remover

Video Face Swap
Swap faces in any video effortlessly with our completely free AI face swap tool!

Hot Article

Hot Tools

Notepad++7.3.1
Easy-to-use and free code editor

SublimeText3 Chinese version
Chinese version, very easy to use

Zend Studio 13.0.1
Powerful PHP integrated development environment

Dreamweaver CS6
Visual web development tools

SublimeText3 Mac version
God-level code editing software (SublimeText3)

Hot Topics











In order to improve the performance of Go applications, we can take the following optimization measures: Caching: Use caching to reduce the number of accesses to the underlying storage and improve performance. Concurrency: Use goroutines and channels to execute lengthy tasks in parallel. Memory Management: Manually manage memory (using the unsafe package) to further optimize performance. To scale out an application we can implement the following techniques: Horizontal Scaling (Horizontal Scaling): Deploying application instances on multiple servers or nodes. Load balancing: Use a load balancer to distribute requests to multiple application instances. Data sharding: Distribute large data sets across multiple databases or storage nodes to improve query performance and scalability.

C++ performance optimization involves a variety of techniques, including: 1. Avoiding dynamic allocation; 2. Using compiler optimization flags; 3. Selecting optimized data structures; 4. Application caching; 5. Parallel programming. The optimization practical case shows how to apply these techniques when finding the longest ascending subsequence in an integer array, improving the algorithm efficiency from O(n^2) to O(nlogn).

Nginx performance tuning can be achieved by adjusting the number of worker processes, connection pool size, enabling Gzip compression and HTTP/2 protocols, and using cache and load balancing. 1. Adjust the number of worker processes and connection pool size: worker_processesauto; events{worker_connections1024;}. 2. Enable Gzip compression and HTTP/2 protocol: http{gzipon;server{listen443sslhttp2;}}. 3. Use cache optimization: http{proxy_cache_path/path/to/cachelevels=1:2k

The performance of Java frameworks can be improved by implementing caching mechanisms, parallel processing, database optimization, and reducing memory consumption. Caching mechanism: Reduce the number of database or API requests and improve performance. Parallel processing: Utilize multi-core CPUs to execute tasks simultaneously to improve throughput. Database optimization: optimize queries, use indexes, configure connection pools, and improve database performance. Reduce memory consumption: Use lightweight frameworks, avoid leaks, and use analysis tools to reduce memory consumption.

Effective techniques for quickly diagnosing PHP performance issues include using Xdebug to obtain performance data and then analyzing the Cachegrind output. Use Blackfire to view request traces and generate performance reports. Examine database queries to identify inefficient queries. Analyze memory usage, view memory allocations and peak usage.

Exception handling affects Java framework performance because when an exception occurs, execution is paused and the exception logic is processed. Tips for optimizing exception handling include: caching exception messages using specific exception types using suppressed exceptions to avoid excessive exception handling

By building mathematical models, conducting simulations and optimizing parameters, C++ can significantly improve rocket engine performance: Build a mathematical model of a rocket engine and describe its behavior. Simulate engine performance and calculate key parameters such as thrust and specific impulse. Identify key parameters and search for optimal values using optimization algorithms such as genetic algorithms. Engine performance is recalculated based on optimized parameters to improve its overall efficiency.

Profiling in Java is used to determine the time and resource consumption in application execution. Implement profiling using JavaVisualVM: Connect to the JVM to enable profiling, set the sampling interval, run the application, stop profiling, and the analysis results display a tree view of the execution time. Methods to optimize performance include: identifying hotspot reduction methods and calling optimization algorithms
