Summary of JavaScript Statements

This chapter introduced each of the statements of the JavaScript language. Table 6-1 summarizes these statements, listing the syntax and purpose of each.

Table 6-1. JavaScript statement syntax

Statement

Syntax

Purpose

break
 
break;
break labelname;

Exit from the innermost loop or switch statement or from the statement named by label. 

case
 
case expression:

Label a statement within a switch statement. 

continue
 
continue; 
continue labelname;

Restart the innermost loop or the loop named by label. 

default
 
default:

Label the default statement within a switch statement. 

do/while
 
do
    statement
while (expression);

An alternative to the while loop.

empty
 
;

Do nothing.

for
 
for (initialize ; test ; increment)
    statement

An easy-to-use loop.

for/in
 
for (variable in object)
    statement

Loop through the properties of an object.

function
 
function funcname([arg1[..., argn]]) {
    statements
}

Declare a function.

if/else
 
if (expression)
    statement1
[else statement2]

Conditionally execute code.

label
 
                              identifier: statement

Give statement the name identifier. 

return
 
return [expression];

Return from a function or return the value of expression from a function. 

switch
 
switch (expression) {
    statements
}

Multiway branch to statements labeled with case or default: . 

throw
 
throw expression;

Throw an exception.

try
 
try {
    statements
}
catch (identifier) {
    statements
}
finally {
    statements
}

Catch an exception.

var
 
var name_1 [ ...

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