function categoryClick(){
    if(gl_form.cat.value==null || gl_form.cat.value==""){
        alert("You should choose a caregory");
        return;
    }
    gl_form.show.value = "category";
    gl_form.submit();
}

function findClick(){
    if (gl_form.find.value == ""){
        alert("You should enter a search word");
        return;
    }
    gl_form.show.value = "find";
    gl_form.submit();
}