Functions in javascript as values, javascript Functions

Functions in javascript as values, javascript Functions

Because the number of functions in ECMAScript is a variable, the function can also be used as a value, that is, not only can the function be passed to another function, but also can be returned as another function.

This function accepts two parameters. The first parameter is a function name, and the second parameter is a value passed to the function.

Function add (num ){

Return num + 10;

}

Var result = callFunction (add, 10 ){

Alert (result); // 20

}

Javascript function as parameter name

A simple example. Test environment: win7 + ie8 + chrome
<Script type = "text/javascript">
Function Add (x, y ){
Alert (x + y );
}
Function Sub (x, y ){
Alert (x-y );
}
Function CallFunc (Fun, x, y ){
If (Fun & (typeof Fun = "function ")){
If (x & y & (typeof x = "number") & (typeof y = "number ")){
Fun (x, y );
} Else {
Console. log (typeof x );
}

} Else {

}
}

CallFunc (Sub, 5, 3 );
</Script>

What is the value in the Function called by Javascript?

You can use global variables to set c as a global variable in other functions.

<Script language = "javascript">
Var c; // defines the global variable c outside the function.
Function A (a, B, c)
{
Var a = 2;
Var B = 3;
C = a * B; // If var is absent in c, it is the global variable.
Var Calcuate1 = document. getElementById ("Calcuate1 ");
Calcuate1.innerText = Calcuate1.innerText + c;
}

Function B (d, e, f)
{
Var d = 4;
// Problem:
Var e // How do I pay the value of C in Function A () to e?
E = c // assign the global variable c to e
Var f = d * e;
Var Calcuate2 = document. getElementById ("Calcuate2 ");
Calcuate2.innerText = Calcuate2.innerText + f;

}

</Script>