"Functions are very important method for a programing language, so please learn it carefully yet they are not very difficult if can understand by logics. Learn functions step by step very care fully don't be afraid they are very easy."
"Functions are very important method for a programing language, so please learn it carefully yet they are not very difficult if can understand by logics. Learn functions step by step very care fully don't be afraid they are very easy."
In simple term we can say functions are reusable codes which we can use multiple times and anywhere in web-page, this depends on developer needs. Functions use some functionality of scopes which we learn in next lesson, now just focus on functions.
We can make or store function into variables by using var keyword and just give a var name to function.
Always remember that in function body we must have to use return keyword, for return implied parameters another function not going to work. We also can use alert or console.log window keyword but return keyword is always best to use. Use return method from inside the function body and display result with alert,console.log, prompt, confirm (Window default keywords) whatever you use from outside the function.
function function-name( parameter 1, parameter 2,...parameter n ) {
return ( parameter 1 , parameter 2, ...parameter n );
}
function-name(passing values of parameters);
function sum ( a , b ) {
return( a + b );
}
alert( sum ( 2, 3 ) );
We implied here two parameters and give two values a = 2 and b = 3 so here we get result 5 by using sum function.
There is nothing change by using var, all functionality of function are same. We are just store function into var keyword.
I think Hope fully you are thinking here that why i need to create a function for Sum or Multiply of 2 and 3. ? But what about in multiple conditions and multi tasking? Let see an another example.
function cal( v1, v2, fn){
return fn(v1,v2);
}
function sum(v1,v2){
return v1 + v2;
}
function min(v1,v2){
return v1-v2;
}
function mul(v1,v2){
return v1 * v2;
}
function div(v1,v2){ //We can also use here different parameters.
return v1/v2;
}
console.log("Value1 = " +40);
console.log("Value2 = " +20);
console.log("Value1 + Value2 = "+(cal (40,20,sum)));
console.log("Value1 - Value2 = "+(cal (40,20,min)));
console.log("Value1 * Value2 = "+(cal (40,20,mul)));
//We can also use different parameters for passing our values into semi functions.
