Flash cards
Review the key moves
What is the main idea behind JavaScript Conditionals?
Lesson checks
Practice each idea before moving on
Short Mimo-style checks built from this lesson's code, terms, and sequence.
Which statement best captures the main point of this lesson?
Complete the missing token from the example code.
code to execute ___ the condition is truePut the learning moves in the order that makes the concept easiest to apply.
Conditional Statements
Conditional Statements allow us to perform different actions for different conditions .
Conditional statements run different code depending on true or false conditions.
Conditional statements include
- if
- if...else
- if...else if...else
- switch
- ternary (? :)
When to use Conditionals
- Use if to specify a code block to be executed, if a specified condition is true
- Use else to specify a code block to be executed, if the same condition is false
- Use else if to specify a new condition to test, if the first condition is false
- Use switch to specify many alternative code blocks to be executed
- Use (? :) (ternary) as a shorthand for if...else
The if Statement
Use if to specify a code block to be executed, if a specified condition is true .
Syntax
if (
condition
) {
//
code to execute if the condition is true
}The else Statement
Use else to specify a code block to be executed, if the same condition is false .
Syntax
if (
condition
) {
//
code to execute if the condition is true
}
else {
//
code to execute if the condition is false
}The else if Statement
Use else if to specify a new condition to test, if the first condition is false .
Syntax
if (
condition1
) {
//
code to execute if condition1 is true
}
else if (
condition2
) {
//
code to execute if the condition1 is false and condition2 is true
} else {
//
code to execute if the condition1 is false and condition2 is false
}The switch Statement
Use switch to specify many alternative code blocks to be executed.
Syntax
switch(
expression
) {
case
x
// code block
break;
case
y
// code block
break;
default:
//
code block
}Ternary Operator (? :)
Use (? :) (ternary) as a shorthand for if...else .
Example
condition
?
expression1
expression2