function alltrim(str)
  {
    // left trim space (这里有效，但SFD的 str.charAt(0)==9什么的就不可以)
    while ( str.charAt(0)==" " && str.length>0)
      {
          if (str.length==1)
           {
             str="";
           } 
          else
          str=str.substr(1);
      }
 
    // right trim space
    while (str.charAt(str.length-1)==" " && str.length>0)
      {
         if (str.length==1)
          {
            str="";
          }
         else
         str=str.substr(0,str.length-1);
      }
  
    return str;
  }



 function valid_email(str)
  {   
    // trim spaces
    str=alltrim(str);

    // if empty or too small (at least a@b.c)
    if (str.length<5) return false;

    // if exist slash
    if (str.indexOf("/")>=0) return false;

    // if exist spaces
    if (str.indexOf(" ")>=0) return false;

    // should be one and only one @
    if (str.indexOf("@")!=str.lastIndexOf("@") || str.indexOf("@")==-1) return false;     
    
    // should be at least one period 
    if (str.indexOf(".")==-1) return false;


   return true;
  }

  function validateForm()
  {
    formObj=document.enquiry_form;

    cp=formObj.contact_person.value;
    cn=formObj.company_name.value;
    tel=formObj.tel.value;
    fax=formObj.fax.value;
    em=formObj.email.value;
    ma=formObj.mailing_address.value;
    c1=formObj.C1.checked;
    c2=formObj.C2.checked;
    c3=formObj.C3.checked;
    c4=formObj.C4.checked;
    c5=formObj.C5.checked;
    c6=formObj.C6.checked;
    c7=formObj.C7.checked;
    c8=formObj.C8.checked;

    lang=formObj.language.value;   
    empty=0;
    place_focus=false;
    req_field=""; 
    if (cp=="")
      {
         if (empty==0)  
            if (lang == "ENG")  
              req_field="contact person";
              
           else 
             { if (lang == "GB")  
                
                  req_field = "联系人";
               else 
                 req_field = "&#32667;&#29586;&#58862; "; 
               } 
                    
          
         else
           {
               if (lang =="ENG") 
               
              req_field=req_field+",contact person"; 
              else  
                 if (lang == "GB") 
                     req_field=req_field+"、联系人 ";
                   else 
                      req_field= req_field+"&#32667;&#36424;&#58862;";
                     
              }
         empty=1;
          
         if (!place_focus)
         {
           formObj.contact_person.focus();
           place_focus=true;
         }
      }

    if (cn=="") {
         if (empty==0)  
     { 
       if(lang =="ENG")  
              req_field="company name";
           else   
               if (lang =="GB") 
                 req_field = "公司名"; 
              else 
                 req_field = "&#12381;&#58999;&#59069;&#22079;";  
             }
        else
           if (lang =="ENG")
             req_field=req_field+",company name";
           else 
             if (lang =="GB") 
              req_field = req_field+"、公司名";
              else  
              req_field = req_field+",&#12381;&#58999;&#59069;&#22079;";
               
        empty=1;

         if (!place_focus)
         {
           formObj.company_name.focus();
           place_focus=true;
         }

      }


    if (tel=="")
      {
         if (empty==0)
           { 
            if (lang == "ENG")     
               req_field="telephone number"; 
               else  
                  if (lang == "GB" )  
                          req_field = "电话" ;
                       else 
                         req_field = "&#31615;&#26464;&#33145;&#32079;"; 
                
              } 
         else 
              if (lang =="ENG") 
                   req_field=req_field+",telephone number";
                else
                   if (lang == "GB")  
                      req_field = req_field+"、电话"; 
                  else 
                     req_field = req_field+",&#31615;&#26464;&#33145;&#32079;";  
                     
         empty=1;

         if (!place_focus)
         {
           formObj.tel.focus();
           place_focus=true;
         }

      }

    if (fax=="")
      {
         if (empty==0) 
            { 
            if (lang == "ENG")     
               req_field="fax  number "; 
               else  
                  if (lang == "GB" )  
                          req_field = "传真" ;
                       else 
                         req_field = "&#32922;&#30199;&#33145;&#32079;"; 
                  
              } 
         else 
              if (lang =="ENG") 
                   req_field=req_field+",fax  number";
                else
                    
                   if (lang == "GB")  
                   req_field=req_field+"、传真";
             else
                   req_field=req_field+",&#32922;&#30199;&#33145;&#32079;";
                 
        
     empty=1;

        if (!place_focus)
         {
           formObj.fax.focus();
           place_focus=true;
         }

      }

    if (em=="")
      {
         if (empty==0) 
           
             if (lang == "ENG")   
                   req_field="email";
             else 
                    if (lang == "GB") 
                        req_field = "电子邮箱" ;
                    else 
                        req_field = "&#31615;&#58898;&#31182;&#12531;"; 
                  
         else 
              if  (lang == "ENG") 
                  req_field=req_field+",email";
               else 
                 if (lang == "GB")  
                    req_field = req_field + "、电子邮箱"; 
                  else  
                    req_field = req_field + ",&#31615;&#58898;&#31182;&#12531;";  
         empty=1;
     
        if (!place_focus)
         {
           formObj.email.focus();
           place_focus=true;
         }

      }

    if (ma=="")
      {
         if (empty==0)
                if (lang == "ENG") 
                    req_field="mailing address";
                else 
                  if (lang == "GB") 
                         req_field = "通讯地址";
                   else 
                        req_field = "&#31182;&#24739;&#59079;&#59203;"; 
                 
         else 
            if (lang == "ENG") 
                 req_field=req_field+",mailing address";
             else 
                {
                 if (lang == "GB")  
                     req_field = req_field +"、通讯地址"; 
                  else 
                     req_field = req_field +", &#31182;&#24739;&#59079;&#59203;";
                }   
         empty=1;  
           if (!place_focus)
         {
           formObj.mailing_address.focus();
           place_focus=true;
         }
      }
 
   if ((!c1) && (!c2) && (!c3) && (!c4) && (!c5) && (!c6) && (!c7) && (!c8))
     {
        if (empty==0) 
          {
            if (lang == "ENG") 
                req_field="businness details";
             else 
                 if (lang =="GB")  
                    req_field = "公司类型";
                 else 
                    req_field = "&#22365;&#31336;&#25720;&#59157;";
                     
                 }  
          else  
             if (lang == "ENG") 
                  req_field=req_field+",businness details";
             else  
                if (lang =="GB") 
                   req_field = req_field+"、公司类型";
                 else 
                    req_field = req_field +",&#22365;&#31336;&#25720;&#59157;"; 
                       
        empty=1;

        if (!place_focus)
         {
           self.location="#BUS_DETAILS";
           place_focus=true;
         }
     }
    
    if ( ((cp=="") || (cn=="") || (tel=="") || (fax=="") || (em=="")  || (ma==""))
     || ((!c1) && (!c2) && (!c3) && (!c4) && (!c5) && (!c6) && (!c7) && (!c8)) ||
     !valid_email(em))
     {
       
     if ( ((cp=="") || (cn=="") || (tel=="") || (fax=="") || (em=="")  || (ma==""))
         || ((!c1) && (!c2) && (!c3) && (!c4) && (!c5) && (!c6) && (!c7) && (!c8)))
     { 
       if  (lang == "ENG")  
         req_field="Please input: "+req_field+".";

        else

         if (lang == "GB")
           req_field = "请输入："+req_field+"。";  

          else   
           req_field = "&#21483;&#22359;&#58864;:" +req_field+":";
           
     }
     else
     {
        req_field="";
     }   
    
     if (!valid_email(em))
       { 
          if (lang == "ENG" ) 
             req_field=req_field+"\n The email is invalid.Please check spelling.";
            else  
                if (lang == "GB") 
                 req_field = req_field + "\n电子邮箱地址错误。请检查拼写。";
              else 
                req_field = req_field + " email &#31002;&#57755;.&#21483;&#28010;&#29737;&#59143;&#57369;&#57524;&#31990;.";
       }  
            alert(req_field);
       return false;
     }
   else
      return true;
  }