Functions in javascript


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Functions in javascript

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Functions in javascript

  1. 1. Disclaimer: This presentation is prepared by trainees of baabtra as a part of mentoring program. This is not official document of baabtra –Mentoring Partner Baabtra-Mentoring Partner is the mentoring division of baabte System Technologies Pvt . Ltd
  2. 2. Typing Speed Week Target Achieved 1 40 21 2 40 23 3 40 27
  3. 3. Jobs Applied Week Company Designation Applied Date Current Status 1 Advent software Sr. Application Engineer 26-8-2013 Short listed 2 Alcatel-lucent Software Engineer 28-8-2013 Waiting 3
  4. 4. Functions in Javascript Muhammed Noufal V T muhammednoufalvt@gmail.c om lvt med-noufal 9744003056
  5. 5. • What is Functions defined) A group of statements that is put together (or once and then can be used (by reference) repeatedly on a Web page • Also known as subprogram, procedure, subroutine • A function is written as a code block (inside curly { } braces), preceded by the function keyword • Syntax js function – function functionname() { some code to be executed } – alert("message") – confirm("message") – prompt("message")
  6. 6. Advantages of Functions • Number of lines of code is reduced • Code becomes easier to read & understand • Code becomes easier to maintain as changes need to be made only at a single location instead multiple
  7. 7. Example • <html> <head> <title>Assignment-2</title> </head> <script> function date() { var d=new Date(); document.write(d); } </script> <body> <p>Press the button to show current date & time... </p> <input type="button" onclick="date()" value="Show date"> </body> </html>
  8. 8. Function Defnitions • • • Format of a function definition function function-name( parameter-list ) { declarations and statements } – Function name any valid identifier – Parameter list names of variables that will receive arguments • Must have same number as function call • May be empty – Declarations and statements • Function body (“block” of code) Return statement – Optional , can return either nothing, or a value – This is required if you want to return a value from a function
  9. 9. Function Parameters • Facility to pass different parameters while calling a function • Passed parameters can be captured inside the function and any manipulation can be done over those parameters • A function can take multiple parameters separated by comma. • Parameters define the interface between the function and the rest of
  10. 10. • <html> Example <head> <script type="text/javascript"> function say(name, age) { alert( "I am" + name + age + " years old."); } </script> </head> <body> <p>Click the following button to Know about my self</p> <form> <input type="button" onclick="say('Baabtra', 2)" value="Myself"> </form> </body> </html>
  11. 11. Local and Global variable • A variable declared (using var) within a JavaScript function becomes LOCAL and can only be accessed from within that function
  12. 12. Contact Us Emarald Mall (Big Bazar Building) Mavoor Road, Kozhikode, Kerala, India. Ph: + 91 – 495 40 25 550 Start up Village Eranakulam, Kerala, India. Email: NC Complex, Near Bus Stand Mukkam, Kozhikode, Kerala, India. Ph: + 91 – 495 40 25 550
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