print "<input name='anyname' value=abc def>";

##</code><code>##

<input name='anyname' value=abc (and some other 
attribute, def, that I don't recognize and which 
does not have a value, so I'll ignore it)>
##</code><code>##

$v = "abc def";
# $v only contains abc def not "abc def"

$html = qq(<input name="anyname" value="$v">);

##</code><code>##

$v = qq("abc def");
# $v now contains <i>"abc def"</i>

$html = "<input name=\"anyname\" value=$v";

# you could also do it like this:
$c = qq("abc def");
$html = qq(<input name="anyname" value=$c>);