>How will add with my query.

>SELECT scode,CODE,descr,fname,descru,fnameu,lcode,sec,sex,rtel FROM student WHERE admtd=1;
>aND lcode>=thisform.lcodefm.value AND lcode<=thisform.lcodeto.value...

It is always better to not use thisform properties in the query.

Use separate variables outside of the query, e.g.

lcMinCode = thisform.lCodeFm.value
lcMaxCode = thisform.lcCodeFm.value

select ... where lCode between m.lcMinCode and m.lcMaxCode ...