jQuery: Evaluate script in ajax response

XML responses from my webapp have both HTML to add to the page AND some have a script to run.

I'm trying to send back XML from my webapp like:

<?xml version="1.0"?>
<doc>
  <html-to-insert>
    <![CDATA[<p>add me to the page</p>]]>
  </html-to-insert>
  <script>
    <![CDATA[ alert('execute me'); ]]>
  </script>
</doc>

What I'm doing now is snapping out the <html-to-insert> and <script> CDATA, inserting the html into the page and eval'ing <script>.

I'm looking for criticism on my approach. Any suggestions from anyone?

Solution 1:

You can use the jQuery library to make the XML request to your backend and also parse it

$(document).ready(function()
{
  $.ajax({
    type: "GET",
    url: "your/url/that/returns/xml",
    dataType: "xml",
    success: function (xml) {
      // xml contains the returned xml from the backend

      $("body").append($(xml).find("html-to-insert").eq(0));
      eval($(xml).find("script").text());
    }
  });
});

You can find out more about jQuery here and here

I haven't tested it, but it should work according to this article.

Solution 2:

You'd rather send JSON, it's way easier to interpret. Example:

// Suppose your response is a string:
// { html: "<p>add me to the page</p>, script:"alert('execute me');" }
var obj = eval( "(" + response + ")" ) ;
eval( obj.script ) ;

Solution 3:

This is the best answer that i found. Work perfect:

element.innerHTML = xmlhttp.responseText;
var scriptElements = element.getElementsByTagName('SCRIPT');
for (i = 0; i < scriptElements.length; i ++) {
    var scriptElement = document.createElement('SCRIPT');
    scriptElement.type = 'text/javascript';
    if (!scriptElements[i].src) {
        scriptElement.innerHTML = scriptElements[i].innerHTML;
    } else {
        scriptElement.src = scriptElements[i].src;
    }
    document.head.appendChild(scriptElement);
}

Thanks to Joseph the Dreamer. Original answer here.

EDIT:

Clarification:

1. scripts only run inside script tag
2. added scripts after document load, only take effect if it is added to the head tag

Thanks to Deniz Porsuk for the comment to improve the answer