[CyberAlien]

If you are using double quotes inside double quoted text, add \ before it:

<strong><phrase 1="$bbuserinfo[username]"><script type="text/javascript">
var d = new Date()
var time = d.getHours()


if (time < $vboptions[time_1]) 
{
document.write("<b><img src=\"$vboptions[imgurl_1]\" /> $vboptions[text_1] $vbphrase[CWMOFH_username]</b>");
}
else if (time > $vboptions[time_1] && time < $vboptions[time_2]) 
{
document.write("<b><img src=\"$vboptions[imgurl_2]\" /> $vboptions[text_2] $vbphrase[CWMOFH_username]</b>");
}
else
{
document.write("<b><img src=\"$vboptions[imgurl_3]\" /> $vboptions[text_3] $vbphrase[CWMOFH_username]</b>")
}
</script></strong></phrase>

And what you are planning to do won't work anyway. Phrases are parsed on server side, javascript is parsed on client side.