Automatic Thumbnail and Read More Function for Blogger

Read more function is used to cut our post on homepage, post will appear fully when we click read more link. It's cut automatically and if we insert image, it appears thumbnail.
This is automatic read more function with thumbnail. We just need to set up our HTML code.
Follow steps:
1. Go to "Design" click "Edit HTML"
2. Tick on "Expand Widget Templates"
3. Find this code
<data:post.body/>
4. Replace with this code below

<b:if cond='data:blog.pageType == "static_page"'>
<data:post.body/>
<b:else/>

<b:if cond='data:blog.pageType != "item"'>

<div expr:id='"summary" + data:post.id'><data:post.body/></div>
<script type='text/javascript'>createSummaryAndThumb("summary<data:post.id/>");
</script> <span class='rmlink' style='float:right;padding-top:20px;'><a expr:href='data:post.url'>read more</a></span>

</b:if>
<b:if cond='data:blog.pageType == "item"'><data:post.body/></b:if>
</b:if>

5. Now, search for </head> and paste the following section of code immediately before it:

<script type='text/javascript'>var thumbnail_mode = "no-float" ;
summary_noimg = 430;
summary_img = 340;
img_thumb_height = 100;
img_thumb_width = 120;
</script>
<script type='text/javascript'>
//<![CDATA[
function removeHtmlTag(strx,chop){
if(strx.indexOf("<")!=-1)
{
var s = strx.split("<");
for(var i=0;i<s.length;i++){
if(s[i].indexOf(">")!=-1){
s[i] = s[i].substring(s[i].indexOf(">")+1,s[i].length);
}
}
strx = s.join("");
}
chop = (chop < strx.length-1) ? chop : strx.length-2;
while(strx.charAt(chop-1)!=' ' && strx.indexOf(' ',chop)!=-1) chop++;
strx = strx.substring(0,chop-1);
return strx+'...';
}

function createSummaryAndThumb(pID){
var div = document.getElementById(pID);
var imgtag = "";
var img = div.getElementsByTagName("img");
var summ = summary_noimg;
if(img.length>=1) {
imgtag = '<span style="float:left; padding:0px 10px 5px 0px;"><img src="'+img[0].src+'" width="'+img_thumb_width+'px" height="'+img_thumb_height+'px"/></span>';
summ = summary_img;
}

var summary = imgtag + '<div>' + removeHtmlTag(div.innerHTML,summ) + '</div>';
div.innerHTML = summary;
}

//]]>
</script>

clarification code above:
summary_noimg = 430; is post cut height without image
summary_img = 340; is post cut height with image
img_thumb_height = 100; is thumbnail image height
img_thumb_width = 120; is thumbnail image width