Hi try this,

$a = 'This is an anchor <a name=_Toc00123998">and these are another<a 
+name=_Toc00123999"><a name=_Toc00124000"> couple.';

(@a) = $a =~ m#(<.*?>)#gsi;
local $"="";
$a =~ s#(<.*?>)##gsi;
print "@a".$a;
[download]

o/p:<a name=_Toc00123998"><a name=_Toc00123999"><a name=_Toc00124000">This is an anchor and these are another couple.