Javascript development technology overview-Chapter 1 javascript Overview

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1.3 javascript and browser

1.4 javascript Functions

From 3 Cschool

What can JavaScript do?

JavaScript provides HTML designers with a programming tool.
HTML creators are often not programmers, but JavaScript is a scripting language with extremely simple syntax! Almost everyone has the ability to put short code snippets into their HTML pages.
JavaScript can add dynamic text to HTML pages.
A JavaScript declaration similar to this can put a variable piece of text on an HTML page: document. write ("JavaScript can respond to events
You can set JavaScript to be executed only when an event occurs. For example, when a page is loaded or an HTML element is clicked.
JavaScript can read and write HTML elements.
JavaScript can read and change the content of HTML elements.
JavaScript can be used to verify data
JavaScript can be used to verify the data before it is submitted to the server.
JavaScript can be used to detect visitors' browsers
JavaScript can be used to detect the visitor's browser and load the corresponding page for the browser based on the detected browser.
JavaScript can be used to create cookies.
JavaScript can be used to store and retrieve information on the visitor's computer.
1.5 limitations of javascript

. It is a client script, so it must be hot in the parser.

. Although dynamic effects can be achieved on webpages, they do not have any graphic processing capabilities.

. It does not contain Internet technologies and cannot read data from databases.

. Most browsers do not allow cross-origin javascript operations.