Question

The following code tries to injuect some code into an iFrame (on the same server as the page). I am getting a ReferenceError: chunks is not defined error. Can somebody help me figure out why please? I’ve been baning my head on this one for a day now.

<iframe id="preview-iframe"></iframe>

<script language="JavaScript" type="text/javascript">
var chunks;
chunks += "<span class=\"bold";
chunks += "\">Hello World!</";
chunks += "span>";
document.getElementById("preview-iframe").src="javascript:void(document.write(chunks))";
</script>

Answer 1

<iframe id="prev-frame"></iframe>

<script language="JavaScript" type="text/javascript">
    var chunks = '';
    chunks += "<span class=\"bold";
    chunks += "\">Hello World!</";
    chunks += "span>";
    document.getElementById("prev-frame").src="javascript:void(document.write('" + chunks + "'))";
</script>

You need to concatanate '" + chunks + "' so that it is not interpreted literally. Also, iframe is a reserved word so I renamed the id on the frame.

🙂