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JavaScript Tutorial


Total available pages count: 33
Subject - JavaScript Frameworks
About About Introduction Introduction Enabling and Embedding Comments Literals Types of Literals Integer Literals Floating-Point Literals Boolean Literals String Literals Escaping Literals Operators Types of Operators Assignment Operators Comparison Operators Arithmetic Operators Logical Operators Variables Variables and usage Values of Variables Data Type Conversion Arrays Arrays Functions What are Functions Defining a Function Calling a Function Objects Objects Conditional statements If Else Else..If Switch Loop statements While Do-while For For-in Break Continue
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Defining a Function

When defining a function, it is very important that you pay close attention to the syntax. Unlike HTML, JavaScript is case sensitive, and it is very important to remember to enclose a function within curly braces { }, separate parameters with commas, and use a semi-colon at the end of your line of code.

It's important to understand the difference between defining and calling a function.
 

Defining the function names the function and specifies what to do when the function is called. You define a function within the <SCRIPT>...</SCRIPT> tags within the <HEAD>...</HEAD> tags. In defining a function, you must also declare the variables which you will be calling in that function.

Here's an example of defining a function:
function Popupalert()
{
  alert('This is an alert box.');
}

 

Defining the function names the function and specifies what to do when the function is called. You define a function within the <SCRIPT>...</SCRIPT> tags within the <HEAD>...</HEAD> tags. In defining a function, you must also declare the variables which you will be calling in that function.

Here's an example of a function that takes a parameter:
function AnotherAlert(word)
{
  alert(word + ' is the word that you clicked on');
}

 

Defining the function names the function and specifies what to do when the function is called. You define a function within the <SCRIPT>...</SCRIPT> tags within the <HEAD>...</HEAD> tags. In defining a function, you must also declare the variables which you will be calling in that function.

Defining the function names the function and specifies what to do when the function is called. You define a function within the <SCRIPT>...</SCRIPT> tags within the <HEAD>...</HEAD> tags. In defining a function, you must also declare the variables which you will be calling in that function.

Here are two examples of passing in multiple parameters when you are defining the function:
function secondAlert(word,password)
{
  confirm(word + ' is the word that you clicked on. The secret password is ' + password);
}

 

function thirdAlert(word,password)
{
  confirm(word + ' is the word you clicked on. Please take note of the password, ' + password);
}

 

Defining the function names the function and specifies what to do when the function is called. You define a function within the <SCRIPT>...</SCRIPT> tags within the <HEAD>...</HEAD> tags. In defining a function, you must also declare the variables which you will be calling in that function.

Defining the function names the function and specifies what to do when the function is called. You define a function within the <SCRIPT>...</SCRIPT> tags within the <HEAD>...</HEAD> tags. In defining a function, you must also declare the variables which you will be calling in that function.



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