The JavaScript Function Invocation is used to execute the function code and it is common to use the term “call a function” instead of “invoke a function”. The code inside a function is executed when the function is invoked.
Syntax:
- Invoking a Function as a Function:
function myFunction( var ) {
return var;
}
myFunction( value );
- Invoking a Function as a Method:
let myObject = {
let : value,
functionName: function () {
return this.let;
}
}
myObject.functionName();
Parameters: It contains two parameters as mentioned above and described below:
- functionName: The functionName method is a function and this function belongs to the object and myObject is the owner of the function.
- this: The parameter this is the object that owns the JavaScript code and in this case the value of this is myObject.
Example 1: This example uses function invocation to add two numbers.
html
<!DOCTYPE html><html lang="en"><head> <title>JavaScript Function Invocation</title></head><body style="text-align:center;"> <h2 style="color:green">GeeksForGeeks</h2> <h4>JavaScript Function Invocation</h4> <p> Function returns the addition of 50 and 60 </p> <p id="neveropen"></p> <!-- Script to add two numbers --> <script> function myFunction(a, b) { return a + b; } document.getElementById("neveropen").innerHTML = window.myFunction(50, 60); </script></body></html> |
Output:
Example 2: This example uses function invocation to concatenate strings.
Javascript
let myObject = { firstName: "Geeks", middleName: "for", lastName: "Geeks", fullName: function () { return this.firstName + this.middleName + this.lastName; }}console.log(myObject.fullName()); |
Output
neveropen
