how to add slashes to only double quotes
<p>i want to add slashes to only double quotes to some html elements  this is how i am doing , but its not working for me :</p>

<pre><code>$str  ="
    &lt;table class="body-wrap" style="font-family: 'Helvetica Neue', 'Helvetica', Helvetica, Arial, sans-serif; width: 100%; margin: 0; padding: 0;"&gt;
    &lt;tr style="font-family: 'Helvetica Neue', 'Helvetica', Helvetica, Arial, sans-serif; margin: 0; padding: 0;"&gt;
    &lt;td style="font-family: 'Helvetica Neue', 'Helvetica', Helvetica, Arial, sans-serif; margin: 0; padding: 0;"&gt;this is my test&lt;/td&gt;&lt;/tr&gt;&lt;/table&gt;&amp;#13;";
</code></pre>

<p>this is my php function :</p>

<pre><code> $str2 = addcslashes($str, '"');
</code></pre>

<p>i think that i have problems at the beginning of my string , i dont know how to declare :</p>

<pre><code>$str  =" or $str  = ' 
</code></pre>

<p>both for me didnt work</p>