The use of links in javascript is usually to prevent search engine robots from spidering these links. Many search engine robots are not able to follow javascript links. This may mean that a link within javascript is not properly “seen” by the robots and therefore cannot be followed to your web site.

An example of a link in javascript:

<script language='JavaScript' type='text/javascript'>
document.write('<a hr'+'ef="ht'+'tp://w'+'ww.ash'+esh'+'.com.np">Ashesh's Blog</a>');
</script>

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rel=”nofollow”, is said to be the next biggest thing to be used by shady webmasters engaging in reciprocal link exchanges. This attribute was introduced by Google as a means to prevent the problem of comment spamming in weblogs, also called “Blogs”, and it looks to be adopted by all other major search engines such as Yahoo! and MSN.

“rel” is an attribute, not a tag
rel=”nofollow” has been inaccurately called a HTML tag. It is in fact an attribute that can be added to HTML tags, similar to adding the attribute “width” to HTML tags such as < IMG > or < TABLE >. The attribute rel=”nofollow” is used on individual anchor tags < A > for links. Read more…