var divIds=['chris', //a list of all the id's you want to toggle
'tyson',
'jimt',
'shona',
'charlotte',
'keri',
'megan',
'jims'];

function togglediv(divid){
var i, div;
for(i=0; (div=document.getElementById(divIds[i])) ;i++){
if(divIds[i]!=divid){
div.style.display = 'none';
}else{
div.style.display = '';
}
}
}