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Dynamic HTML #12: JavaScript - Part II

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أستاذ المادة حيدر محمد حبيب الخميس       17/12/2012 09:04:44
Conditional Operator
JavaScript also contains a conditional operator that assigns a value to a variable based on some condition.
Syntax
variablename=(condition)?value1:value2

Example
grade=(mark>=50)?"Pass ":"Fail ";

If the variable mark is greater than or equal value of 50, then the variable grade will be assigned the value "Pass" else it will be assigned "Fail".

JavaScript If...Else Statements
Conditional statements are used to perform different actions based on different conditions.

Conditional Statements
Very often when you write code, you want to perform different actions for different decisions. You can use conditional statements in your code to do this.
In JavaScript we have the following conditional statements:
• if statement - use this statement to execute some code only if a specified condition is true
• if...else statement - use this statement to execute some code if the condition is true and another code if the condition is false
• if...else if....else statement - use this statement to select one of many blocks of code to be executed
• switch statement - use this statement to select one of many blocks of code to be executed

If Statement
Use the if statement to execute some code only if a specified condition is true.
Syntax
if (condition)
{
code to be executed if condition is true
}

Note that if is written in lowercase letters. Using uppercase letters (IF) will generate a JavaScript error!

If...else Statement
Use the if....else statement to execute some code if a condition is true and another code if the condition is not true.
Syntax
if (condition)
{
code to be executed if condition is true
}
else
{
code to be executed if condition is not true
}

Note that if is written in lowercase letters. Using uppercase letters (IF) will generate a JavaScript error!

If...else if...else Statement
Use the if....else if...else statement to select one of several blocks of code to be executed.
Syntax
if (condition1)
{
code to be executed if condition1 is true
}
else if (condition2)
{
code to be executed if condition2 is true
}
else
{
code to be executed if condition1 and condition2 are not true
}


المادة المعروضة اعلاه هي مدخل الى المحاضرة المرفوعة بواسطة استاذ(ة) المادة . وقد تبدو لك غير متكاملة . حيث يضع استاذ المادة في بعض الاحيان فقط الجزء الاول من المحاضرة من اجل الاطلاع على ما ستقوم بتحميله لاحقا . في نظام التعليم الالكتروني نوفر هذه الخدمة لكي نبقيك على اطلاع حول محتوى الملف الذي ستقوم بتحميله .
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