JavaScript Language Basics 12

When using the IF statement, if you encounter many conditions, you should not continue to use the IF statement, JavaScript provides a more efficient alternative, that is the switch statement, we first look at the switch statement template:

In the above we can see that the switch statement consists of the following parts:
Conditional expression, Case statement, break statement, default statement.
1) The switch statement starts with the keyword switch and places the conditional expression in parentheses after the Switch keyword.
2) The purpose of the case statement is to check whether the condition matches (the switch statement can contain more than n case statements).
3) The action of the break statement is to tell JavaScript to stop execution here and jump off the switch statement. Of course, you can omit the break statement, after omitting, the statement will continue to execute until the break statement or switch statement execution is complete.
4) The default statement indicates that all case statements do not match when they are executed, and of course the default statement can be omitted.

The code after the break statement is omitted:
Omitting the break statement shows that the above is done from Case 1 down until the break statement at the default statement is stopped (and the break statement of the default statement is omitted, the result is the same as above).
If a reasonable collocation of the case statement and the location of the break statement can write some better logic code.



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JavaScript Language Basics 12