Try the following.
<html:select property="category" style="width:155px" tabindex="12">
1opt<html

ption value="" >- - - -Select- - - - </html

ption>2opt<html

ption value="...">...</html

ption>
3opt<html

ption value="...">...</html

ption>
4opt<html

ption value="...">...</html

ption>
5opt<html

ption value="...">...</html

ption>
</html:select>
Observe the above code.Don't provide the value to 1opt(first option).It'll work fine.
Regards
Suri.