javascript.pptx
- 1. S.Muthuganesh M.Sc.,B.Ed., Assistant Professor Department of Computer Science Vivekananda College
- 2. Introduction • Javascript as it lightweight dynamic programming language. • Programs in this language are called Scripts. • JavaScript often abbreviated JS, is a programming language that is one of the core technologies of the World Wide Web, alongside HTML and CSS. • JavaScript can be implemented using JavaScript statements that are placed within the <script>... </script> HTML tags in a web page.
- 3. Advantages • Simplicity JavaScript is relatively simple to learn and implement. • Speed JavaScript is an ‘interpreted’ language, it reduces the time required by other programming languages. • Popularity JavaScript is used everywhere on the web. • Web Development JavaScript is commonly used for creating web pages. It allows us to add dynamic behavior to the webpage and add special effects to the webpage. On websites, it is mainly used for validation purposes. • Games Create games that operate inside the browser.
- 4. How to Run • Open any text editor(eg: notepad, notepad++ etc.) <html> <head> <title>First program</title> <script type=“text/javascript”> </script> </head> <body> document.wite(“Hello Welcome”); </body> </html> • Save as demo.html • Run in any browser
- 5. variable • A JavaScript variable is simply a name of the value. • There are two types of variables in JavaScript : local variable and global variable. • There are some rules while declaring a JavaScript variable (also known as identifiers). 1. Name must start with a letter (a to z or A to Z), underscore( _ ) 2. After first letter we can use digits (0 to 9) 3. JavaScript variables are case sensitive, for example x and X are different variables.
- 6. Data types • JavaScript is a dynamic type language, means you don't need to specify type of the variable. • You need to use var here to specify the data type. It can hold any type of values such as numbers, strings etc. Data Type Description String represents sequence of characters e.g. "hello" Number represents numeric values e.g. 100 Boolean represents boolean value either false or true Null represents null i.e. no value at all NAN Not a Number
- 7. document.write() • This is used to display a given text in a web page. Syntax document.write(“Statements”); document.write(“Helloworld!!!”);
- 8. Dialog Boxes • JavaScript supports three important types of dialog boxes • Alert Dialog Box An alert dialog box is mostly used to give a warning message to the users. Alert box gives only one button "OK" to select and proceed. • Confirmation Dialog Box A confirmation dialog box is mostly used to take user's consent on any option. It displays a dialog box with two buttons: OK and Cancel. If the user clicks on the OK button, will return true. If the user clicks on the Cancel button, then will return false • Prompt Dialog Box The prompt dialog box is very useful when you want to pop-up a text box to get user input. Thus, it enables you to interact with the user. The user needs to fill in the field and then click OK.
- 9. JavaScript Operators • JavaScript operators are symbols that are used to perform operations on operands There are following types of operators in JavaScript. Arithmetic Operators(+,-,*,/,%) Comparison (Relational) Operators(<,>,<=,>=,==,===,!=,!==) Bitwise Operators(&,|,~,<<,>>) Logical Operators(&&,||,!) Assignment Operators(=,+=,-=,*=,/=,%=)
- 10. Thank you