I guess you could use regexp for this:
/\s([\w]{1,}=)((?!")[\w]{1,}(?!"))/g
\s match any white space character [\r\n\t\f ]
1st Capturing group ([\w]{1,}=)
[\w]{1,} match a single character present in the list below
Quantifier: {1,} Between 1 and unlimited times, as many times as possible, giving back as needed [greedy]
\w match any word character [a-zA-Z0-9_]
= matches the character = literally
2nd Capturing group ((?!")[\w]{1,}(?!"))
(?!") Negative Lookahead - Assert that it is impossible to match the regex below
" matches the characters " literally
[\w]{1,} match a single character present in the list below
Quantifier: {1,} Between 1 and unlimited times, as many times as possible, giving back as needed [greedy]
\w match any word character [a-zA-Z0-9_]
(?!") Negative Lookahead - Assert that it is impossible to match the regex below
" matches the characters " literally
g modifier: global. All matches (don't return on first match)
Which would be implemented something like this:
echo preg_replace_callback('/\s([\w]{1,}=)((?!")[\w]{1,}(?!"))/', function($matches){
return ' '.$matches[1].'"'.$matches[2].'"';
}, $str);
And would result in:
<td width="140" style='width:105.0pt;padding:0cm 0cm 0cm 0cm'>
<p class="MsoNormal"><span style='font-size:9.0pt;font-family:"Arial","sans-serif";
mso-fareast-font-family:"Times New Roman";color:#666666'>OCCUPANCY
TAX:</span></p>
</td>
Eval.in live example
Note, this is a down and dirty example, and can surely be cleaned up.