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Lesson 3 Client-side technologies
Objective Describe the functionality provided by client-side scripts.
A script is a program usually written in a scripting language that functions as the glue between programs. Scripts are used to perform various functions at the client workstation (or client-side) in Web browsers or on Web servers.

Client-side scripts

Client-side scripts are embedded in HTML pages. Client-side scripts are used to perform the following functions:
  1. Provide drop-down menus
  2. Open a browser window
  3. Generate events such as a MouseOver; that is, a change in graphics or text when a user's mouse moves over an element
  4. Check for a plug-in or a particular browser version
  5. Validate user input; for example, information supplied in a form before the user submits it
  6. Display error or informational pop-ups
Because the code relies on the browser, developers should be aware of the following limitations:
  1. There may be limited browser support for some functions.
  2. Visitors can disable JavaScript and/or JScript in their browser's preferences.

If your client-side script is not functioning properly, it is probably the browser's fault. Client-side script: A program written in a scripting language used to perform various functions at the client workstation.
Client-side scripts are embedded in HTML pages.


Java applets and ActiveX

The following paragraph discusses client-side programs which were used during the dotcom era. The dot-com era was a historic period of speculation mainly in the United States that occurred roughly from 1994 to 2000, which was a period of extreme growth and adoption of the Internet. Java applets also are small programs written in the Java language. Their use is discouraged against because they are slow on the front end and pose a security risk.
During this same time period, Microsoft integrated ActiveX with its Internet Explorer browser. ActiveX was the technology Microsoft used up to Internet Explorer 11 and has been repalced with Silver light for their Microsoft Edge browser. ActiveX has been discontinued with the release of Microsoft Edge and was typically used (up to Internet Explorer 11) to add user interface functions.
The following illustration of the dynamic stock quote is a Java applet.

Twitter Stockquote
Twitter Stock Quote

WebProgramming - Languages - Quiz

Click the Quiz link below to test your knowledge of terms and concepts regarding types of programming languages.
WebProgramming - Languages - Quiz