Website outbound access slow, slow to open web pages, should be how to optimize?

　　Site visits slow, slow to open web pages, should be how to optimize?
　　IIS7 website monitoring
　　test whether the site was hijacked site opens speed detection, the title was changed and other information.
　　Slow page the following main reasons: First, the network bandwidth is not enough network bandwidth is the most important factor, that is not enough broadband. The same site, if broadband high speed access will be significantly faster.
　　Solution: looking for operators to increase bandwidth.
　　Two, http request too many times
　　to address: http reduce the number of requests.
　　Map: put multiple images integrated into the picture in order to locate the position of a hyperlink.
　　CSS Sprites merge pictures to show the elements specified by the CSS backgroud-image and backgroud-position.
　　Merge JS scripts and CSS stylesheets.
　　Use external JS and CSS files.
　　Three, DNS resolution speed DNS resolution is resolved from the domain name to IP.
　　DNS resolution and comprising a number of reciprocally parsing every time it takes to resolve, i.e., the product of both of them is the total time it takes for DNS resolution. Many people ignore the factors that DNS resolution, in fact, its website parsing speed is also very important.
　　Solution: Replace the relatively low latency DNS server.
　　Fourth, the time is too long to receive data, such as downloading resource is too large
　　to resolve: to compress HTTP transport, that js, css, pictures and other resources on the basis of already compressed, compressed again in the HTTP transmission process. The client can support compression by Accept-Encoding up statement browser, the server to enable compression by Content-Encoding, compressed configuration file type, compression mode. Lossless compression using gzip compression for best results, have become the most widely used, most browsers support data compression format.
　　Fifth, the server and client hardware configuration in the same network environment, dual-core server computing power is stronger bound. Also in the client, the same network environment, you use a machine with Intel i7 processor and i3 processors to open the same page, speed is certainly not the same.
　　Solution: upgrade the hardware configuration.
　　Sixth, too much web resources
　　Resolution: Using CDN deployment network to improve download speed, you can distribute free web resources through a CDN provider.
　　Seven, page content too many
　　pages that contain a lot of pictures untreated, if these pictures is large, it will lead to open slowly. Others such as Flash and video files, will affect the access speed, while redundant code is one of the factors slowing down the speed of the site.
　　Resolution: The owners need to try to optimize the code, with a minimum of code to achieve the best results.
　　Eight, JavaScript script is too large, blocking the loading of a page
　　using javascript effects on the site is taboo, not only can not be crawled search engine, but also because of repeated requests to the server, resulting in added burden on the server, the site becomes slow.
　　Resolution: The scripts in JavaScript before </ body> tag. When the script is not async and defer, JS file will be executed immediately after downloading. In this case, script blocking at the top of the page will appear, in the case of Suman will result in "black and white" until the download is complete before continuing script render the page. Therefore, script at the bottom of the page allows presented as soon as possible.