switch (type){
    case "S":
        s_td_1.className = "s_on";
        move_xjt.colSpan = 1;
        f.i_k.name = "search";
        f.action = "/trade/catalog.asp<%=weblink_add%>";
        f.business_type.value = "S";
case "B":
        s_td_3.className = "s_on";
        move_xjt.colSpan = 3;
        f.action = "/trade/catalog.asp<%=weblink_add%>";
        f.business_type.value = "B";
case "O":
        s_td_4.className = "s_on";
        move_xjt.colSpan = 7;
        f.i_k.name = "search";
        f.action = "/trade/catalog.asp<%=weblink_add%>";
        f.business_type.value = "O";
case "G":
        s_td_6.className = "s_on";
        move_xjt.colSpan = 9;
        f.i_k.name = "search";
        f.action = "/trade/catalog.asp<%=weblink_add%>";
        f.business_type.value = "G";
    case "P":
        s_td_2.className = "s_on";
        move_xjt.colSpan = 11;
        f.i_k.name = "search";
        f.action = "/trade/catalog.asp<%=weblink_add%>";
        f.business_type.value = "P";
    case "Company":
        s_td_7.className = "s_on";
        move_xjt.colSpan = 5;
        f.action = "/company/index.asp<%=weblink_add%>";
        f.business_type.value = "Company";
    case "information":
        s_td_8.className = "s_on";
        move_xjt.colSpan = 13;
        f.i_k.name = "search";
        f.action = "/information/catalog.asp<%=weblink_add%>";
        f.business_type.value = "information";
}


为什么我用的时候多个条件都成立了