Mass-fixed all AJAX functions to also check the HTTP status code before parsing the response
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">
<head>
<title>{#searchreplace_dlg.replace_title}</title>
<script type="text/javascript" src="../../tiny_mce_popup.js"></script>
<script type="text/javascript" src="../../utils/mctabs.js"></script>
<script type="text/javascript" src="../../utils/form_utils.js"></script>
<script type="text/javascript" src="js/searchreplace.js"></script>
<link rel="stylesheet" type="text/css" href="css/searchreplace.css" />
<base target="_self" />
</head>
<body style="display:none;">
<form onsubmit="return false;" action="#">
<div class="tabs">
<ul>
<li id="search_tab"><span><a href="javascript:SearchReplaceDialog.switchMode('search');" onmousedown="return false;">{#searchreplace.search_desc}</a></span></li>
<li id="replace_tab"><span><a href="javascript:SearchReplaceDialog.switchMode('replace');" onmousedown="return false;">{#searchreplace_dlg.replace}</a></span></li>
</ul>
</div>
<div class="panel_wrapper">
<div id="search_panel" class="panel">
<table border="0" cellspacing="0" cellpadding="2">
<tr>
<td><label for="search_panel_searchstring">{#searchreplace_dlg.findwhat}</label></td>
<td><input type="text" id="search_panel_searchstring" name="search_panel_searchstring" style="width: 200px" /></td>
</tr>
<tr>
<td colspan="2">
<table border="0" cellspacing="0" cellpadding="0" class="direction">
<tr>
<td><label>{#searchreplace_dlg.direction}</label></td>
<td><input id="search_panel_backwardsu" name="search_panel_backwards" class="radio" type="radio" /></td>
<td><label for="search_panel_backwardsu">{#searchreplace_dlg.up}</label></td>
<td><input id="search_panel_backwardsd" name="search_panel_backwards" class="radio" type="radio" checked="checked" /></td>
<td><label for="search_panel_backwardsd">{#searchreplace_dlg.down}</label></td>
</tr>
</table>
</td>
</tr>
<tr>
<td colspan="2">
<table border="0" cellspacing="0" cellpadding="0">
<tr>
<td><input id="search_panel_casesensitivebox" name="search_panel_casesensitivebox" class="checkbox" type="checkbox" /></td>
<td><label for="search_panel_casesensitivebox">{#searchreplace_dlg.mcase}</label></td>
</tr>
</table>
</td>
</tr>
</table>
</div>
<div id="replace_panel" class="panel">
<table border="0" cellspacing="0" cellpadding="2">
<tr>
<td><label for="replace_panel_searchstring">{#searchreplace_dlg.findwhat}</label></td>
<td><input type="text" id="replace_panel_searchstring" name="replace_panel_searchstring" style="width: 200px" /></td>
</tr>
<tr>
<td><label for="replace_panel_replacestring">{#searchreplace_dlg.replacewith}</label></td>
<td><input type="text" id="replace_panel_replacestring" name="replace_panel_replacestring" style="width: 200px" /></td>
</tr>
<tr>
<td colspan="2">
<table border="0" cellspacing="0" cellpadding="0" class="direction">
<tr>
<td><label>{#searchreplace_dlg.direction}</label></td>
<td><input id="replace_panel_backwardsu" name="replace_panel_backwards" class="radio" type="radio" /></td>
<td><label for="replace_panel_backwardsu">{#searchreplace_dlg.up}</label></td>
<td><input id="replace_panel_backwardsd" name="replace_panel_backwards" class="radio" type="radio" checked="checked" /></td>
<td><label for="replace_panel_backwardsd">{#searchreplace_dlg.down}</label></td>
</tr>
</table>
</td>
</tr>
<tr>
<td colspan="2">
<table border="0" cellspacing="0" cellpadding="0">
<tr>
<td><input id="replace_panel_casesensitivebox" name="replace_panel_casesensitivebox" class="checkbox" type="checkbox" /></td>
<td><label for="replace_panel_casesensitivebox">{#searchreplace_dlg.mcase}</label></td>
</tr>
</table>
</td>
</tr>
</table>
</div>
</div>
<div class="mceActionPanel">
<div style="float: left">
<input type="button" id="insert" name="insert" value="{#searchreplace_dlg.findnext}" onclick="SearchReplaceDialog.searchNext('none');" />
<span id="replace_buttons">
<input type="button" class="button" id="replaceBtn" name="replaceBtn" value="{#searchreplace_dlg.replace}" onclick="SearchReplaceDialog.searchNext('current');" />
<input type="button" class="button" id="replaceAllBtn" name="replaceAllBtn" value="{#searchreplace_dlg.replaceall}" onclick="SearchReplaceDialog.searchNext('all');" />
</span>
</div>
<div style="float: right">
<input type="button" id="cancel" name="cancel" value="{#cancel}" onclick="tinyMCEPopup.close();" />
</div>
</div>
</form>
</body>
</html>