Whats this long script in page source. What it is used for?

Question

The script below was embedded in the head section of the html page just below the <meta> tags. Can anyone explain what the purpose is of putting such a long script in the head section without content?

<script type="text/javascript">
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</script>
<script type="text/javascript">
    if (top.location != self.location)
    top.location = self.location;
</script>

Answer 1

The first script is New Relic Browser monitoring allowing them to see how long the page load was etc. Here's a post from someone researching this a few years back, new relic message board post

If you are looking to remove it you will need to either modify your New Relic config file, or modify how/when it is loaded. I found this resource to be useful in removing it.

The second script is accurately discussed in the approved answer.

Answer 2

The second <script> tag in your question is referred to a frame busting code. It breaks a framed document out to the top level.

top.location != self.location when the current document is not at the top level in the window (e.g. it's in a frame or iframe).

And, top.location = self.location; sets the current URL into the top level of the window - thus breaking it out of any frame and moving it to the top level of the window.

This is done by sites that want to prevent being framed. You can read a more detailed description here.

---

Modern browsers support a newer means of preventing framing with the X-Frame-Options header. See a description here.

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For anyone interesting in what that first <script> tag is see this discussion. It appears to be some sort of page tracking script.