Function in Java script

Function in javascript:

DataType : Function is a datatype in javascript as other datatype like var,string and date.

e.g:

function checktype()

{}

alert(typeof(checktype));

As mentioned above function is datatype so we can assign function to variable, pass function as parameter to a function and can return as value.

Ex1:-

var funVal= function add(n1,n2)

{

return n1+n2;

}

funVal(8,19);

Ex2:-

function addValues(n1,n2)

{

return function(){

return n1+n2;

}

}

var retFnc= addValues(8,9);

retFnc();

Ex3:-

function addvalues(fns,fnr,n1,n2)

{

fns();

print(n1+n2);

fnr();

}

function fns(){

print("Execution start:");

}

function fnr()

{

print ("Execution end:");

}

addValues(fns,fnr,23,89);

Because function is datatype there are some methods associated with it:

1. call

2. apply

1) call takes 1or more than one parameter as calling parameters

function addValues(n1,n2)

{

return n1,n2;

}

addValues.call(null,5,6);

2) apply is different for call as if there is no of parameter is not fixed better approach is to use apply method.

function addValues()

{

for(var i=0;i

{

print(arguments[i].toString());

}

}

addValues.apply(null,[4,6,7]);

addValues.apply(null, [34,31,23,45]);

One more thing is associated with function that i would like to talk is context we are also able to use context inside javascript function.

Ex:-

var thisContext= { val=0;}

function addValue(n1)

{

return this.val+n1;

}

print(addValue.call(thisContext,n1));

is the way use controls in jQuery.

Ex:

$("#btnOk").click(function {

this.Value+="Clicked!!!!";

});

Happy Programming :)

Let knowledge flow like water!!!!!!!!!!!!!