Common sources of unterminated string literal

Question

I am trying to debug a JavaScript script that gets read in a Firefox extension and executed  I only can see errors via the Firebug console  my code is invisible to Firebug   and it s reporting a  unterminated string literal     I checked the line and the lines around it and everything seems fine-parentheses  braces  and quotes are balanced  etc  What are other possible causes that I should be looking for

User · Answer

Maybe it s because you have a line break in your PHP code  If you need line breaks in your alert window message  include it as an escaped syntax at the end of each line in your PHP code  I usually do it the following way    message    line 1   n    message     line 2

User · Answer

Look for linebreaks  Those are often the cause

User · Answer

If you ve done any cut paste  some online syntax highlighters will mangle single and double quotes  turning them into formatted quote pairs  matched opening and closing pairs     tho i can t find any examples right now      So that entails hitting Command-  a few times and staring at your quote characters  Try a different font   also  different editors and IDEs use different tokenizers and highlight rules  and JS is one of more dynamic languages to parse  so try opening the file in emacs  vim  gedit  with JS plugins      If you get lucky  one of them will show a long purple string running through the end of file

User · Answer

I ve had trouble with angled quotes in the past         usually from copy and pasting from Word   Replacing them with regular single quotes       does the trick

User · Answer

Try a  binary search   Delete half the code and try again  If the error is still there  delete half the remaining code  If the error is not there  put what you deleted back in  and delete half of that  Repeat    You should be able to narrow it down to a few line fairly quickly  My experience has been that at this point  you will notice some stupid malformed string   It may be expedient to perform this on a saved version of the HTML output to the browser  if you re not sure which server-side resource the error is in

User · Answer

If you ve done any cut paste  some online syntax highlighters will mangle single and double quotes  turning them into formatted quote pairs  matched opening and closing pairs     tho i can t find any examples right now      So that entails hitting Command-  a few times and staring at your quote characters  Try a different font   also  different editors and IDEs use different tokenizers and highlight rules  and JS is one of more dynamic languages to parse  so try opening the file in emacs  vim  gedit  with JS plugins      If you get lucky  one of them will show a long purple string running through the end of file

User · Answer

Whitespace is another issue I find  causes this error  Using a function to trim the whitespace may help

User · Answer

Have you escaped your forward slashes       I ve had trouble with those before

User · Answer

I would vote for jamtoday s answer if I had the  reputation   If your data is coming by way of PHP  this might help   str   str replace array   r     n         str

User · Answer

str   str replace array  quot  r n quot   quot  n r quot   quot  r quot    quot  n quot      lt br   gt    stripslashes  str     This should work

User · Answer

The web page developer guessed wrong about which encoding is used by the viewer s browser   This can usually be solved by specifying an encoding in the page s header

User · Answer

If nothing helps  look for some uni-code characters like   u2028   this may break your string on more than one line and throw this error

User · Answer

Maybe it s because you have a line break in your PHP code  If you need line breaks in your alert window message  include it as an escaped syntax at the end of each line in your PHP code  I usually do it the following way    message    line 1   n    message     line 2

User · Answer

Look for linebreaks  Those are often the cause

User · Answer

Try a  binary search   Delete half the code and try again  If the error is still there  delete half the remaining code  If the error is not there  put what you deleted back in  and delete half of that  Repeat    You should be able to narrow it down to a few line fairly quickly  My experience has been that at this point  you will notice some stupid malformed string   It may be expedient to perform this on a saved version of the HTML output to the browser  if you re not sure which server-side resource the error is in

User · Answer

Also  keep in mind that  0A is the linefeed character URL encoded  It took me awhile to find where there was a linefeed in my offending code

User · Answer

Have you escaped your forward slashes       I ve had trouble with those before

User · Answer

You might try running the script through JSLint

User · Answer

I just discovered that   lt   script gt   appears to work as well as   lt  scr   ipt gt

User · Answer

Look for a string which contains an unescaped single qoute that may be inserted by some server side code

User · Answer

Have you escaped your forward slashes       I ve had trouble with those before

User · Answer

The web page developer guessed wrong about which encoding is used by the viewer s browser   This can usually be solved by specifying an encoding in the page s header

User · Answer

str   str replace array  quot  r n quot   quot  n r quot   quot  r quot    quot  n quot      lt br   gt    stripslashes  str     This should work

User · Answer

Scan the code that comes before the line  mentioned by error message  Whatever is unterminated has resulted in something downstream   the blamed line    to be flagged

User · Answer

Look for a string which contains an unescaped single qoute that may be inserted by some server side code

User · Answer

If you ve done any cut paste  some online syntax highlighters will mangle single and double quotes  turning them into formatted quote pairs  matched opening and closing pairs     tho i can t find any examples right now      So that entails hitting Command-  a few times and staring at your quote characters  Try a different font   also  different editors and IDEs use different tokenizers and highlight rules  and JS is one of more dynamic languages to parse  so try opening the file in emacs  vim  gedit  with JS plugins      If you get lucky  one of them will show a long purple string running through the end of file

User · Answer

You might try running the script through JSLint

User · Answer

You might try running the script through JSLint

User · Answer

Scan the code that comes before the line  mentioned by error message  Whatever is unterminated has resulted in something downstream   the blamed line    to be flagged

User · Answer

Most browsers seem to have problems with code like this   var foo     lt  script gt      In Firefox  Opera and IE8 this results in an unterminated string literal error  Can be pretty nasty when serializing html code which includes scripts

User · Answer

If nothing helps  look for some uni-code characters like   u2028   this may break your string on more than one line and throw this error

User · Answer

Look for a string which contains an unescaped single qoute that may be inserted by some server side code

User · Answer

The web page developer guessed wrong about which encoding is used by the viewer s browser   This can usually be solved by specifying an encoding in the page s header

User · Answer

Also  keep in mind that  0A is the linefeed character URL encoded  It took me awhile to find where there was a linefeed in my offending code

User · Answer

I ve had trouble with angled quotes in the past         usually from copy and pasting from Word   Replacing them with regular single quotes       does the trick

User · Answer

Have you tried Chromebug  It s the Firebug for extensions

User · Answer

Just escape your tag closures or use ascii code  ie   lt   script gt    ie   lt  amp  47 script gt

User · Answer

I just discovered that   lt   script gt   appears to work as well as   lt  scr   ipt gt

User · Answer

You might try running the script through JSLint

User · Answer

Look for linebreaks  Those are often the cause

User · Answer

Try a  binary search   Delete half the code and try again  If the error is still there  delete half the remaining code  If the error is not there  put what you deleted back in  and delete half of that  Repeat    You should be able to narrow it down to a few line fairly quickly  My experience has been that at this point  you will notice some stupid malformed string   It may be expedient to perform this on a saved version of the HTML output to the browser  if you re not sure which server-side resource the error is in

User · Answer

Look for a string which contains an unescaped single qoute that may be inserted by some server side code

User · Answer

Scan the code that comes before the line  mentioned by error message  Whatever is unterminated has resulted in something downstream   the blamed line    to be flagged

User · Answer

Just escape your tag closures or use ascii code  ie   lt   script gt    ie   lt  amp  47 script gt

User · Answer

Whitespace is another issue I find  causes this error  Using a function to trim the whitespace may help

User · Answer

Have you tried Chromebug  It s the Firebug for extensions

User · Answer

Most browsers seem to have problems with code like this   var foo     lt  script gt      In Firefox  Opera and IE8 this results in an unterminated string literal error  Can be pretty nasty when serializing html code which includes scripts

User · Answer

The web page developer guessed wrong about which encoding is used by the viewer s browser   This can usually be solved by specifying an encoding in the page s header

User · Answer

Try a  binary search   Delete half the code and try again  If the error is still there  delete half the remaining code  If the error is not there  put what you deleted back in  and delete half of that  Repeat    You should be able to narrow it down to a few line fairly quickly  My experience has been that at this point  you will notice some stupid malformed string   It may be expedient to perform this on a saved version of the HTML output to the browser  if you re not sure which server-side resource the error is in

User · Answer

Have you escaped your forward slashes       I ve had trouble with those before

User · Answer

I would vote for jamtoday s answer if I had the  reputation   If your data is coming by way of PHP  this might help   str   str replace array   r     n         str

User · Answer

If you ve done any cut paste  some online syntax highlighters will mangle single and double quotes  turning them into formatted quote pairs  matched opening and closing pairs     tho i can t find any examples right now      So that entails hitting Command-  a few times and staring at your quote characters  Try a different font   also  different editors and IDEs use different tokenizers and highlight rules  and JS is one of more dynamic languages to parse  so try opening the file in emacs  vim  gedit  with JS plugins      If you get lucky  one of them will show a long purple string running through the end of file

User · Answer

Scan the code that comes before the line  mentioned by error message  Whatever is unterminated has resulted in something downstream   the blamed line    to be flagged

User · Answer

Look for linebreaks  Those are often the cause

[javascript] Common sources of unterminated string literal

Examples related to javascript

Examples related to debugging

Examples related to firefox-addon