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1. Htttps
HTTPS (full name: Hyper Text Transfer Protocol over secure Socket Layer), is a security-targeted HTTP channel, which is simply the security version of HTTP
The main differences between HTTPS and HTTP are the following four points: (from Baidu Encyclopedia) one, the HTTPS protocol requires a certificate to the CA, the general free certificate is very small, the need for payment. Second, HTTP is a Hypertext Transfer Protocol, the information is plaintext transmission, HTTPS is a secure SSL encryption Transfer protocol. Third, HTTP and HTTPS use a completely different way of connection, with the same port, the former is 80, the latter is 443. Four, HTTP connection is very simple, is stateless; The HTTPS protocol is a network protocol built by the SSL+HTTP protocol to encrypt the transmission and authentication, which is more secure than the HTTP protocol.2. Relative path and absolute path
In HTML, the concept of absolute and relative paths is involved whenever a file is involved (such as hyperlinks, images, etc.). 1. Absolute path (summary from Summer Snow Winter blog) Absolute path refers to the path that the file really exists on the hard disk. For example "bg.jpg" This picture is stored in the hard disk "E:\book\ page layout code \ 2nd Chapter" directory, then "bg.jpg" the absolute path of this picture is "E:\book\ page cloth \ Code \ 2nd Chapter \bg.jpg". Then you should use the following statement if you want to specify the background picture of a Web page using an absolute path: <body backround= "E:\book\ page layout \ code \ 2nd \bg.jpg" > 2. Disadvantages of using absolute paths In fact, in the Web page programming, rarely use absolute path, if use "E:\book\ page cloth \ Code \ 2nd Chapter \bg.jpg" To specify the location of the background picture, browsing on their own computer may be all right, but uploaded to the Web server browsing is likely not to display the picture. Since uploading to a Web server, it is possible that the entire Web site does not have an E drive on the Web server, possibly a D or H drive. Even if placed in the Web server e-disk, the Web server e-disk will not necessarily exist "E:\book\ page layout \ Code \ 2nd Chapter" This directory, so when browsing the Web page will not display the picture. 3. Relative paths in order to avoid this occurrence, it is common to select a relative path when specifying a file in a Web page. The so-called relative path is relative to its own target file location. For example, the "s1.htm" file refers to the "bg.jpg" image, because the "bg.jpg" image is in the same directory as the "s1.htm", then use the following code in the "s1.htm" file, as long as the relative position of the two files is unchanged ( That is, in the same directory), you can display the image correctly in the browser regardless of where you upload it to the Web server. Note: The relative path uses the "/" character as the separator character for the directory, and the absolute path can use the "\" or "/" character as the delimiter character for the directory. Since the "IMG" Directory is a subdirectory under the "2nd Chapter" directory, there is no need to add the "/" character before "IMG". Often used in relative paths ". /"to represent the previous level of the directory. If there are multiple top-level catalogs, you can use more than one ". /", for example" http://www.cnblogs.com/"represents the upper parent directory. 4. Relative virtual directory Relative paths There is also a comparison"Relative virtual directory". Take a look at the following example: <body background= "/img/bg.jpg" > in this example, the value of the Background property is "/img/ Bg.jpg ", note that there is a"/"character before" IMG ". This "/" represents the root directory of the virtual directory. Assuming that the "E:\book\ page layout \ Code" is set to the virtual directory, then "/img/bg.jpg" The Real path is "E:\book\ page layout \ Code \img \bg.jpg", if the "E:\book\ page layout \ Code \ 2nd" Set as a virtual directory, then The true path of "/img/bg.jpg" is "E:\book\ page layout \ Code \ 2nd Chapter \img\bg.jpg" ************************1. The real directory is the directory where the files are stored on your computer's hard drive, for example: E:\Website, E:\Website\Image is the real directory
2. A virtual directory is a directory structure that is displayed when a user browses a Web site or FPT for HTTP access. For example, you set the E:\Website on IIS to access the directory. Then E:\Website is the root directory of the virtual directory; E:\Website\Image, it becomes \image. The structure after becoming a virtual directory is the following root directory
|_image
It can be seen that this directory is virtual, not the real directory on the computer, but the access is stronger than the real directory, in the design of the site more convenient. Because sometimes the computer that designs the Web page is different from the computer that is accessed on the Internet. It may be different to place a real directory of files. Some on the e-plate, some on the D-plate. But through the virtual directory, the directory is unified, which is the design of the Web page requirements.
Jump to the specified page in 3.js:
1) document.location.assign ("...");
2) window.location = ' ... ';
3) location.href = ' http://www.baidu.com ';
https/relative path, absolute path
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