JavaScript switch statement evaluates a switch condition, base on switch condition value matched case will run until break or end of case statement.
Syntax
switch (condition){
case value1:
// Do stuff if value1 is true
[break;]
case value2:
// Do stuff if value2 is true
[break;]
...
...
case valueN:
// Do stuff if valueN is true
[break;]
default:
// Execute default if none of the case are execute
[break;]
}
break keyword is optional for end of the case statement execute.
break; is strongly recommended for preventing execute all other case statements.
Example: with break keyword
<script>
var weekname = "wednesday";
switch (weekname) {
case "monday":
document.writeln("Monday working day.");
break;
case "tuesday":
document.writeln("Tuesday working day.");
break;
case "wednesday":
document.writeln("Wednesday government holiday.");
break;
case "thursday":
document.writeln("Thursday working day.");
break;
case "friday":
document.writeln("Friday is a last working day of the week.");
break;
case "saturday":
document.writeln("Saturday week end.");
break;
case "sunday":
document.writeln("Sunday week end.");
break;
default:
document.writeln("No any case found.");
// last line end of the case statement, no need to write break; keyword
}
</script>
Example Result
Switch statement (without break keyword)
Case 1 :
Without
break; keyword matching case execute. Not only matching case but after all cases and default cases are execute.
Example: without break keyword
<script>
var weekname = "wednesday";
switch (weekname) {
case "monday":
document.writeln("Monday working day.");
case "tuesday":
document.writeln("Tuesday working day.");
case "wednesday":
document.writeln("Wednesday government holiday.");
case "thursday":
document.writeln("Thursday working day.");
case "friday":
document.writeln("Friday is a last working day of the week.");
case "saturday":
document.writeln("Saturday week end.");
case "sunday":
document.writeln("Sunday week end.");
default:
document.writeln("No any case found.");
}
</script>
Example Result
Case 2:
In some case I am missing to write
break; keyword. Switch case execute the matching Case (case "wednesday"_ also execute after cases until next break; keyword. No matter if cases value are not satisfy (Case "thursday") still cases are execute.
Example: execute until next break keyword
<script>
var weekname = "wednesday";
switch (weekname) {
case "monday":
document.writeln("Monday working day.");
break;
case "tuesday":
document.writeln("Tuesday working day.");
break;
case "wednesday":
document.writeln("Wednesday government holiday.");
case "thursday":
document.writeln("Thursday working day.");
break;
case "friday":
document.writeln("Friday is a last working day of the week.");
break;
case "saturday":
document.writeln("Saturday week end.");
break;
case "sunday":
document.writeln("Sunday week end.");
break;
default:
document.writeln("No any case found.");
}
</script>
Example Result
Switch statement use for check case range
Switch statement condition must be set true to check the cases range and execute the matched case otherwise execute default.
Example: execute until next break keyword
<script>
var bdate = 20;
switch (true) {
case bdate >= 1 && bdate <= 10: // Use Logical AND
document.writeln("bdate between 1 to 10 date.");
break;
case bdate >= 11 && bdate <= 20: // Use Logical AND
document.writeln("bdate between 11 to 20 date.");
break;
case bdate >= 21 || bdate <= 30: // Use Logical OR
document.writeln("bdate between 21 to 30 date.");
break;
default:
document.writeln("No any case found.");
}
</script>
Example Result
