Simple XML Question -

alright, using xml editor check validation i'm getting "validation stopped @ line 2, column 8: no declaration found element 'staff'. know why is?

also, every 3 staff members of different type , each type include different elements (adjunct staff members have email, name, position instance, while fulltime types have information of elements.) bad form have element data left blank? if they're staffmembers of different type, alright rid of elements or every staffmember need same elements way through? thanks!

<staff>      <staffmember type="fulltime">         <name>richard baskerville</name>         <position>professor</position>         <officephone>(404) 413-7362</officephone>         <building>robinson college</building>         <room>919</room>         <url>www.cis.gsu.edu/~rbaskerv</url>         <email>rbaskerville@cis.gsu.edu</email>         <degreeinfo>ph. d., m.s., b.s.</degreeinfo>         <research> information systems security, interaction of information systems , organizations, qualitative research methods,      diffusion of innovations, knowledge management</research>     </staffmember>      <staffmember type ="fulltime">         <name>michael gallivan</name>         <position>associate professor</position>         <officephone>(404) 413-7363</officephone>         <building>robinson college</building>         <room>935</room>         <url>www.cis.gsu.edu/~mgalliva</url>         <email>mgalliva@cis.gsu.edu</email>         <degreeinfo>ph. d., m.b.a., m.p.h., b.a.</degreeinfo>         <research> human resource management, management of outsourcing, adoption , diffusion of innovations, organizational learning innovations </research>     </staffmember>        <staffmember type ="fulltime">         <name>sidney harris</name>         <position>professor</position>         <officephone>(404) 413-7017</officephone>         <building>robinson college</building>         <room>427</room>         <url>www2.gsu.edu/~wwwseh/</url>         <email>sidneyharris@gsu.edu</email>         <degreeinfo>ph. d., m.s., b.s.</degreeinfo>         <research> strategic management of technology, global practices in technological innovation , management, regional studies on china , asia culture of high performance organization</research>     </staffmember>        <staffmember type ="adjunct">         <name>arash akhlaghi</name>         <position>adjunct professor</position>         <officephone></officephone>         <building></building>         <room></room>         <url></url>         <email>aakhlaghi1@student.gsu.edu</email>         <degreeinfo></degreeinfo>         <research></research>     </staffmember>      <staffmember type="adjunct">         <name>catherine baird</name>         <position>adjunct professor</position>         <officephone></officephone>         <building></building>         <room></room>         <url></url>         <email>cbaird@cis.gsu.edu</email>         <degreeinfo></degreeinfo>         <research></research>     </staffmember>      <staffmember type="adjunct">         <name>david bloomquist</name>         <position>adjunct professor</position>         <officephone></officephone>         <building></building>         <room></room>         <url></url>         <email>dbloomquist@cis.gsu.edu</email>         <degreeinfo></degreeinfo>         <research></research>     </staffmember>      <staffmember type="staff">         <name>desiree plummer</name>         <position>pc system specialist</position>         <officephone>(404) 413-7440></officephone>         <building>robinson college</building>         <room>908</room>         <url></url>         <email>dplummer@cis.gsu.edu</email>         <degreeinfo></degreeinfo>         <research></research>     </staffmember>      <staffmember type="staff">         <name>walter rich</name>         <position>manager, cis external affairs</position>         <officephone>(404) 413-7398></officephone>         <building>robinson college</building>         <room>929</room>         <url></url>         <email>wrich@cis.gsu.edu</email>         <degreeinfo></degreeinfo>         <research></research>     </staffmember>      <staffmember type="staff">         <name>james sneed</name>         <position>information technology department manager</position>         <officephone>(404) 413-7383></officephone>         <building>robinson college</building>         <room>907</room>         <url></url>         <email>jsneed@cis.gsu.edu</email>         <degreeinfo></degreeinfo>         <research></research>     </staffmember>    <staffmember type="ph.d">         <name>anouck adrot</name>         <position></position>         <officephone>(404) 413-7389></officephone>         <building>robinson college</building>         <room>910</room>         <url></url>         <email>aadrot1@student.gsu.edu</email>         <degreeinfo></degreeinfo>         <research></research>     </staffmember>      <staffmember type="ph.d">         <name>chad anderson</name>         <position></position>         <officephone>(404) 413-7389></officephone>         <building>robinson college</building>         <room>910</room>         <url></url>         <email>canderson32@comcast.net</email>         <degreeinfo></degreeinfo>         <research></research>     </staffmember>      <staffmember type="ph.d">         <name>mathieu chauvet</name>         <position></position>         <officephone>(404) 413-7389></officephone>         <building>robinson college</building>         <room>910</room>         <url></url>         <email>mchauvet1@student.gsu.edu</email>         <degreeinfo></degreeinfo>         <research></research>     </staffmember>  </staff> 

this xml validator doesn't give error xml.

anyway, if use schema or dtd validate, may have error (if doesn't correspond specification).

for second point, can have empty node use depends on needs, on specification if use 1 , code use xml. can delete them if you're not using schema or dtd suspect or if code parse afterward take care of it.