SyntaxError: missing variable name
The JavaScript exception "missing variable name" is a common error experienced by developers. It mostly occurs due to a typo or a forgotten variable name.
Message
SyntaxError: missing variable name (Firefox)
SyntaxError: Unexpected token = (Chrome)
Error type
What went wrong?
A variable is missing a name. The cause is most likely a typo or a forgotten variable name.
Make sure that you've provided the name of the variable before the =
sign.
When declaring multiple variables at the same time, make sure that the previous lines/declaration does not end with a comma instead of a semi-colon.
Examples
Missing a variable name
var = "foo";
Coming up with a descriptive variable name is challenging for most developers. It gets easier over time.
var description = "foo";
Reserved keywords can't be variable names
There are a few variable names that are reserved keywords. You can't use these. Sorry :(
var debugger = "whoop";
// SyntaxError: missing variable name
Declaring multiple variables
Pay special attention to commas when declaring multiple variables. Is there an excess comma? Did you accidentally add commas instead of semicolons?
var x, y = "foo",
var x, = "foo"
var first = document.getElementById('one'),
var second = document.getElementById('two'),
// SyntaxError: missing variable name
The fixed version:
var x, y = "foo";
var x = "foo";
var first = document.getElementById('one');
var second = document.getElementById('two');
Arrays
Array
literals in JavaScript need square brackets around the values. This
won't work:
var arr = 1,2,3,4,5;
// SyntaxError: missing variable name
This would be correct:
var arr = [1,2,3,4,5];