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C # tutorial
The switch statement is used to perform different actions based on different conditions
Use the switch
statement to select one of many code blocks to be executed.
Syntax
This is how it works:
The getDay()
method returns the weekday as a number between
0 and 6.
(Sunday=0, Monday=1, Tuesday=2 ..)
This example uses the weekday number to calculate the weekday name:
switch (new Date().getDay()) {
case 0:
day = "Sunday";
break;
case 1:
day = "Monday";
break;
case 2:
day = "Tuesday";
break;
case 3:
day = "Wednesday";
break;
case 4:
day = "Thursday";
break;
case 5:
day = "Friday";
break;
case 6:
day = "Saturday";
}
The result of day will be:
When JavaScript reaches a break
keyword, it breaks out of the switch block.
This will stop the execution inside the switch block.
It is not necessary to break the last case in a switch block. The block breaks (ends) there anyway.
Note: If you omit the break statement, the next case will be executed even if the evaluation does not match the case.
The default
keyword specifies the code to run if there is no
case match:
The getDay()
method returns the weekday as a number between
0 and 6.
If today is neither Saturday (6) nor Sunday (0), write a default message:
switch (new Date().getDay()) {
case 6:
text = "Today is Saturday";
break;
case 0:
text = "Today is Sunday";
break;
default:
text = "Looking forward to the Weekend";
}
The result of text will be:
The default
case does not have to be the last case in a switch
block:
switch (new Date().getDay()) {
default:
text = "Looking forward to the Weekend";
break;
case 6:
text = "Today is Saturday";
break;
case 0:
text = "Today is Sunday";
}
If default
is not the last case in the switch block, remember to end the default case with a break.
Sometimes you will want different switch cases to use the same code.
In this example case 4 and 5 share the same code block, and 0 and 6 share another code block:
switch (new Date().getDay()) {
case 4:
case 5:
text = "Soon it is Weekend";
break;
case 0:
case 6:
text = "It is Weekend";
break;
default:
text = "Looking forward to the Weekend";
}
If multiple cases matches a case value, the first case is selected.
If no matching cases are found, the program continues to the default label.
If no default label is found, the program continues to the statement(s) after the switch.
Switch cases use strict comparison (===).
The values must be of the same type to match.
A strict comparison can only be true if the operands are of the same type.
In this example there will be no match for x:
let x = "0";
switch (x) {
case 0:
text = "Off";
break;
case 1:
text = "On";
break;
default:
text = "No value found";
}
Create a switch
statement that will alert "Hello" if fruits
is "banana", and "Welcome" if fruits
is "apple".
(fruits) { "Banana": alert("Hello") break; "Apple": alert("Welcome") break; }