function CheckSearchUserForm(FormName){
    if(
        (document.forms[FormName].search_user_name.value=="Wpisz tutaj fragment nicka...")||
        (document.forms[FormName].search_user_name.value=="")
    ){
        window.alert("Wpisz fragment nicka.");
        document.forms[FormName].search_user_name.focus();
        return false;
    }
}
<!-- sprawdzanie formularza edycji profilu -->
function CheckEditUserProfileForm(){
    test_new_user_login=/^[0-9a-zA-Z._-]+$/;
    if((document.form.new_user_login.value.length<3)||(document.form.new_user_login.value.length>16)||(test_new_user_login.test(document.form.new_user_login.value)==false)){
        window.alert("Wpisz poprawny login: 3 do 16 znaków.");
        return false;
    }
    test_new_user_email=/^[0-9a-zA-Z._-]+\@[0-9a-zA-Z_-]+\.[0-9a-zA-Z.]+$/;
    if((document.form.new_user_email.value=="")||(test_new_user_email.test(document.form.new_user_email.value)==false)){
        window.alert("Wpisz poprawny adres email.");
        return false;
    }
    if(document.form.new_user_password.value!=""){
        if((document.form.new_user_password.value.length<3)||(document.form.new_user_password.value.length>16)){
            window.alert("Wpisz poprawne hasło: 3 do 16 znaków.");
            return false;
        }
        if(document.form.new_user_password.value!=document.form.new_re_user_password.value){
            window.alert("Wpisane hasła nie są identyczne");
            return false;
        }
    }
    test_new_user_birthday_date=/^([0-9]{2})+.([0-9]{2})+.([0-9]{4})+$/;
    if(document.form.new_user_birthday_date.value!=""){
        if(test_new_user_birthday_date.test(document.form.new_user_birthday_date.value)==false){
            window.alert("Wpisz poprawny format daty urodzin dd.mm.rrrr");
            return false;
        }
    }
    test_new_user_nameday_date=/^([0-9]{2})+.([0-9]{2})+$/;
    if(document.form.new_user_nameday_date.value!=""){
        if(test_new_user_nameday_date.test(document.form.new_user_nameday_date.value)==false){
            window.alert("Wpisz poprawny format daty imienin dd.mm");
            return false;
        }
    }
}
function ChangeEmblemPreview(FormName){
    document.forms[FormName].EmblemPreviewElement.src = "emblems/"+document.forms[FormName].new_user_emblem_file_name.options[document.forms[FormName].new_user_emblem_file_name.selectedIndex].value;
}
function ShowEmblemsGallery(){
    window.open("popups/emblems_gallery.php","emblemsWindow","resizable=1,left=0,top=0,scrollbars=1");
}
//////////////////////////////
// Rysowanie listy użytkowników
//////////////////////////////
function DisplayUsersList(GetUsersListArray){
    for(a=0;a<GetUsersListArray.length;a++){
        GetUsersListArraySplit = GetUsersListArray[a].split("[%|%]");
        document.write('<tr>');
            document.write('<td class="body_table_text" style="text-align:center;">'+GetUsersListArraySplit[0]+'</td>');
            document.write('<td class="body_table_text" style="text-align:center;"><a class="body_table_text" href="users.php?u='+GetUsersListArraySplit[0]+'" title="Zobacz profil: '+GetUsersListArraySplit[1]+'">'+GetUsersListArraySplit[1]+'</a></td>');
            document.write('<td class="body_table_text" style="text-align:center;">'+GetUsersListArraySplit[2]+'</td>');
            document.write('<td class="body_table_text" style="text-align:center;">'+GetUsersListArraySplit[3]+'</td>');
            document.write('<td class="body_table_text" style="text-align:center;">'+GetUsersListArraySplit[4]+'</td>');
        document.write('</tr>');
    }
}