The JavaScript error "unterminated string literal" occurs when there is an unterminated
String
somewhere. String literals must be enclosed by single (
'
) or double (
"
) quotes.
SyntaxError: Unterminated string constant (Edge) SyntaxError: unterminated string literal (Firefox)
There is an unterminated
String
somewhere. String literals must be enclosed by single (
'
) or double (
"
) quotes. JavaScript makes no distinction between single-quoted strings and double-quoted strings.
Escape sequences
work in strings created with either single or double quotes. To fix this error, check if:
You can't split a string across multiple lines like this in JavaScript:
var longString = 'This is a very long string which needs
to wrap across multiple lines because
otherwise my code is unreadable.';
// SyntaxError: unterminated string literal
Instead, use the
+ operator
, a backslash, or
template literals
。
+
operator variant looks like this:
var longString = 'This is a very long string which needs ' +
'to wrap across multiple lines because ' +
'otherwise my code is unreadable.';
Or you can use the backslash character ("\") at the end of each line to indicate that the string will continue on the next line. Make sure there is no space or any other character after the backslash (except for a line break), or as an indent; otherwise it will not work. That form looks like this:
var longString = 'This is a very long string which needs \ to wrap across multiple lines because \ otherwise my code is unreadable.';
Another possibility is to use template literals , which are supported in ECMAScript 2015 environments:
var longString = `This is a very long string which needs
to wrap across multiple lines because
otherwise my code is unreadable.`;