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Quote unquoted HTML attributes (regular expression)

Posted on 2004-03-31
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Last Modified: 2013-11-19
I need a regular expression that looks at every tag in a string of HTML.
If there are any attributes in a tag that are not surrounded by quotes (' or ") it will add them.

E.g.
$text = '<P class=MsoNormal style="MARGIN: 0cm 0cm 0pt"><FONT face=Times New Roman size=3>my text here</FONT></P>';
$text = preg_replace(this is where I need help!);

and $text becomes....

$text = '<P class="MsoNormal" style="MARGIN: 0cm 0cm 0pt"><FONT face="Times New Roman" size="3">my text here</FONT></P>';
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Question by:jfowlie
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Expert Comment

by:shmert
ID: 10729241
I'd recommend using the PEAR tidy extension to clean up the HTML.
http://pecl.php.net/package/tidy
It does good stuff.  You'll have a hard time doing this with a regular expression, because you need to handle:
- nested quotes
- backslash-escaped quotes
- quoted angle brackets
and other weirdness.  Tidy will do this and a lot more for you.
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Author Comment

by:jfowlie
ID: 10732743
Sorry, I should have said that I'm already making  use of the Tidy extension, and it's good, but it doesn't do everything that I need it to do which is why I was trying to perform a regular expression on the "untidy" html.

Basically the problem I'm having concerns a tag such as the following, where the font face has not been put in quotes
e.g.
<font face=Times New Roman>my text here</font>
I'm running Tidy as follows:

tidy_parse_string($HTMLtext);

tidy_setopt( 'bare' , true );
tidy_setopt( 'drop-proprietary-attributes' , true);
tidy_setopt( 'show-body-only' , true);
tidy_setopt( 'word-2000' , true );
tidy_setopt( 'fix-backslash' ,true);
tidy_setopt( 'logical-emphasis' ,true);
tidy_setopt( 'lower-literals' ,true);
tidy_setopt( 'drop-empty-paras', true);

tidy_clean_repair();

$HTMLtext= tidy_get_output();

And using the settings above, Tidy does the following:
<FONT face=times roman="" new="">my text here</FONT>

I don't understand why it does this when I have 'drop-proprietary-attributes' enabled.

I do not want it to drop the font tags.
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Expert Comment

by:shmert
ID: 10735187
<font face=Times New Roman>my text here</font>
This seems really problematic to me.  How do you know where the attribute value ends and the next attribute name starts?

For example:
<option value=my value selected class=x>

"selected" is a standalone tag!  How can a parser differentiate "my value" from "selected"?  This might be something that can't be reasonably automated.  If the attributes didn't contain spaces, you could just close the quote when you come to a space, and the next non-angled-bracket you come to is the start of a new tag.
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Author Comment

by:jfowlie
ID: 10735375
You're right - the example you gave is a problem.

The following idea is not perfect and it will corrupt your example, but I think it would meet my requirements.  
How would I write something that put everything after an opening attribute= in quotes until it either
1) reached the end of the tag
or
2) came across another attribute (that uses =)

At the end of the day, I have HTML content that is being pasted from Word (which Tidy does a good job of handling)  or other web pages (which are the main culprit for the issue I'm having). The good news is that FORM elements are never part of this content.

Alternatively, can you suggest some better options for me to use with Tidy?
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Accepted Solution

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shmert earned 250 total points
ID: 10745571
Maybe you can do it with regex, although it certainly won't handle every situation (single quotes surrounded by double quotes, for example, like many javascript tags might have).

I'd probably do some sort of iterative parser that looks at the HTML one character at a time.  Have various flags that you set for when you encounter an opening tag, whether you are in a quote block, and the last potential spot where an attribute value ended.
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Assisted Solution

by:skullnobrains
skullnobrains earned 250 total points
ID: 10750238
i would use something that does not really work like a parser but should be usefull
$dest is destination string
$orig is original string
i assume that you converted all '>' and '<' to html entities in the regular text
this will generate an error if u have an '=' sign in an attribute (which is often the case)
it only accepts double-quotes but easy to change
you'll need to check for commas and parenthesis if u need the code

function strtochr($haystack, $needle)
{
   $pos = strrpos($haystack, $needle);
   if($pos === false) {
       return $haystack;
   }
   return substr($haystack, 0, $pos + 1);
}//took this one in the manual


while($orig[$i] != \0){

if(($dest.= $orig[$i]) != '<')continue;

$chunks=explode('=',substr($orig,$i, ($i=strpos($orig,'>') ) );
//i wander if this one is legal. should increment i to the '>' char and output chunks seperated by '=' for the content inside '<...>'

$nb=count($chunks);

for($n=1:$n<(count($chunk)-1);$n++){
   $begin=strtochr(trim($chunks[$n]),' ');
   if($begin[0]!='"')$begin='"'.$begin;
   if($begin[strlen($begin)]!='"')$begin.='"';
   $chunks[$n]=$begin." ".strrchr($chunks[$n+1],' ');}

$chunk[$n]=trim(chunk[$n]);
if($chunk[$n][0]!='"')$begin='"'.$chunk[$n];
if($chunk[$n][strlen(chunk[$n])]!='"')chunk[$n].='"';

$dest.=implode('='$chunks);
}
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Expert Comment

by:skullnobrains
ID: 10750245
$nb=count($chunks);//line nopt necessary

a few $chunks are typed as $chunk : these are typo errors
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LVL 26

Expert Comment

by:skullnobrains
ID: 12667519
thanks a lot for forced accept.
work somtimes gets a reward as it seems :)

just a tiny note, as i looked my code for some time before i figured out what it does... '"' is actually a double-quote embedded between two simple quotes. may help others some day...

see you all on the threads sometimes.
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