this will work:
<script>
function setb(obj)
{
if(obj.value=='')
{obj.value='Search...'; obj.className='search-default';}
else if(obj.value!='' && obj.value!='Search...')
obj.className='search-userinput';
}
function setf(obj)
{
if(obj.value=='Search...')
{obj.value=''; obj.className='search-userinput';}
else
obj.className='search-userinput';
}
</script>
<form action="index.php" method="post" class="search">
<input name="searchword" id="mod_search_searchword" maxlength="20"
type="text" size="30" value="Search..."
onblur="setb(this)"
onfocus="setf(this)" class="search-userinput">
<input type="hidden" name="option" value="com_search">
<input type="hidden" name="task" value="search">
</form>
and we dont have elseif
! that's else if
.