Related Posts Widget for Blogger

This widget or hack call it how you like is often requested by fellow bloggers.

Here is the tutorial how to install related posts based on labels underneath your blog posts.

First of all you must know that it won`˙t work if your labels use any reserved url characters.

Go to templates edit html and click on expand widget templates and copy the whole code inside a plain text editor like notepad. You might consider backing up your template if something runs wrong.

Now paste the following in the page header :

<script type="text/javascript">
//<![CDATA[
var relatedTitles = new Array();
var relatedTitlesNum = 0;
var relatedUrls = new Array();
function related_results_labels(json) {
for (var i = 0; i < json.feed.entry.length; i++) {
var entry = json.feed.entry[i];
relatedTitles[relatedTitlesNum] = entry.title.$t;
for (var k = 0; k < entry.link.length; k++) {
if (entry.link[k].rel == 'alternate') {
relatedUrls[relatedTitlesNum] = entry.link[k].href;
relatedTitlesNum++;
break;
}
}
}
}
function removeRelatedDuplicates() {
var tmp = new Array(0);
var tmp2 = new Array(0);
for(var i = 0; i < relatedUrls.length; i++) {
if(!contains(tmp, relatedUrls[i])) {
tmp.length += 1;
tmp[tmp.length - 1] = relatedUrls[i];
tmp2.length += 1;
tmp2[tmp2.length - 1] = relatedTitles[i];
}
}
relatedTitles = tmp2;
relatedUrls = tmp;
}
function contains(a, e) {
for(var j = 0; j < a.length; j++) if (a[j]==e) return true;
return false;
}
function printRelatedLabels() {
var r = Math.floor((relatedTitles.length - 1) * Math.random());
var i = 0;
document.write('<ul>');
while (i < relatedTitles.length && i < 20) {
document.write('<li><a href="' + relatedUrls[r] + '">' + relatedTitles[r] + '</a></li>');
if (r < relatedTitles.length - 1) {
r++;
} else {
r = 0;
}
i++;
}
document.write('</ul>');
}
//]]>
</script>

Scroll down to the blog1 widget, and find the following:

<b:if cond='data:post.labels'>
<data:postLabelsLabel/>
<b:loop values='data:post.labels' var='label'>
<a expr:href='data:label.url' rel='tag'><data:label.name/></a><b:if cond='data:label.isLast != "true"'>,</b:if>
</b:loop>
</b:if>

and change it to :

<b:if cond='data:post.labels'>
<data:postLabelsLabel/>
<b:loop values='data:post.labels' var='label'>
<a expr:href='data:label.url' rel='tag'><data:label.name/></a><b:if cond='data:label.isLast != "true"'>,</b:if>
<b:if cond='data:blog.pageType == "item"'>
<script expr:src='"/feeds/posts/default/-/" + data:label.name + "?alt=json-in-script&amp;callback=related_results_labels&amp;max-results=10"' type='text/javascript'/>
</b:if>
</b:loop>
</b:if>

Save the code back to your template html and go to page elements and add a new HTML/Javascript widget underneath the main blog posts widget with this code :

<script type="text/javascript">
removeRelatedDuplicates();
printRelatedLabels();
</script>

Now go back to Template -> Edit HTML, check the check box to expand the template code, and find the HTML/Javascript widget you just added. It'll look something like the following. Add the lines in bold:

<b:widget id='HTML13' locked='false' title='Related Posts' type='HTML'>
<b:includable id='main'>
<b:if cond='data:blog.pageType == "item"'>
<!-- only display title if it's non-empty -->
<b:if cond='data:title != ""'>
<h2 class='title'><data:title/></h2>
</b:if>
<div class='widget-content'>
<data:content/>
</div>

<b:include name='quickedit'/>
</b:if>
</b:includable>
</b:widget>

There's a few numbers you can tweak to show more or less related posts. In the first code box there is a part that says i < results="10.">

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