In
JavaScript, a function can be called using any number of arguments. Suppose if
a function is defined with 4 arguments, it is not necessary to pass all the 4
arguments while calling the function.
For
example,
function
processData(a, b, c, d){
}
Above
function can be processed like below.
processData(10);
processData(10,
20);
processData(10,
20, 30);
processData(10,
20, 30, 40);
processData(10,
20, 30, 40, 50); //50 is unnamed argument
processData(10,
20, 30, 40, 50, 60); // 50 and 60 are unnamed arguments
function.html
<!DOCTYPE html> <html> <head> <title>function arguments</title> </head> <body> <script type="text/javascript"> function processData(a, b, c, d) { document.write("a = " + a + " b = " + b + " c = " + c + " d = " + d + "<br /><br />"); } processData(10); processData(10, 20); processData(10, 20, 30); processData(10, 20, 30, 40); processData(10, 20, 30, 40, 50); </script> </body> </html>
Open above
page in browser, you can able to see following data.
a = 10 b =
undefined c = undefined d = undefined
a = 10 b =
20 c = undefined d = undefined
a = 10 b =
20 c = 30 d = undefined
a = 10 b =
20 c = 30 d = 40
a = 10 b =
20 c = 30 d = 40
Accessing unnamed arguments of a
function
By using
arguments keyword, you can access all the arguments passed to the function.
function
processData(a){
for(var i=0; i<arguments.length;
i++) {
document.write(arguments[i] +
" ");
}
document.write("<br /><br
/>");
}
functionArgs.html
<!DOCTYPE html> <html> <head> <title>Function Arguments</title> </head> <body> <script type="text/javascript"> function processData(a) { document.write("Arguments are : "); for (var i = 0; i < arguments.length; i++) { document.write(arguments[i] + " "); } document.write("<br /><br />"); } processData(); processData(10); processData(10, 20); processData(10, 20, 30); </script> </body> </html>
Open above
page in a browser, you can able to see following data.
Arguments
are :
Arguments
are : 10
Arguments
are : 10 20
Arguments
are : 10 20 30
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