php - how to add slashes to only double quotes -

i want add slashes double quotes html elements how doing , not working me :

$str  ="     <table class="body-wrap" style="font-family: 'helvetica neue', 'helvetica', helvetica, arial, sans-serif; width: 100%; margin: 0; padding: 0;">     <tr style="font-family: 'helvetica neue', 'helvetica', helvetica, arial, sans-serif; margin: 0; padding: 0;">     <td style="font-family: 'helvetica neue', 'helvetica', helvetica, arial, sans-serif; margin: 0; padding: 0;">this test</td></tr></table>&#13;"; 

this php function :

 $str2 = addcslashes($str, '"'); 

i think have problems @ beginning of string , dont know how declare :

$str  =" or $str  = '  

both me didnt work

delete string $str =" or $str = ' entirely wrong.

1) use css style sheet store css outside html , avoid repetition.

2) use single quotes in html syntax (and php string in double quotes) avoid need escape html @ (javascript elements exception, however).

example of points 1 , 2 combined:

css file

.body_wrap_table {       width: 100%;  } .table_td_tr {     font-family: 'helvetica neue', 'helvetica', helvetica, arial, sans-serif;           margin: 0;        padding: 0; } 

html php string

$str = " <table class='body-wrap body_wrap_table'>     <tr class='table_td_tr'>     <td class='table_td_tr'>this test</td></tr></table> "; 

so no need quote escaping @ all.

3) if want can use regex function such preg_replace exampled here:

$str = preg_replace('/"+(?<!\\")/', '\"', $str); 

this regex match " character not preceeded \ character, , replace escaped quote.

4) possibly simpler approach may or may not solution (and less processor heavy regex) use str_replace such :

$str = str_replace("\"","\\\",$str);  

this replaces text fitting shape " \" may cause double escaping if quote has escape mark preceeding it.

references:

• regex matching if not preceded else

• use preg_replace replace character unless escape character precedes