function HideContent(x) {
 if(x.length < 1) { return; }
 document.getElementById(x).style.display = "none";
}

function ShowContent(x) {
 if(x.length < 1) { return; }
 document.getElementById(x).style.display = "block";

 if(x == 'link1') {
  HideContent('link2');
  HideContent('link3');
  HideContent('link4');
  HideContent('link5');
  HideContent('link6');
  HideContent('link7');
  HideContent('link8');
  HideContent('link9');
  HideContent('link10');
  HideContent('link11');
  HideContent('link12');
 }
 
 else if(x == 'link2') {
  HideContent('link1');
  HideContent('link3');
  HideContent('link4');
  HideContent('link5');
  HideContent('link6');
  HideContent('link7');
  HideContent('link8');
  HideContent('link9');
  HideContent('link10');
  HideContent('link11');
  HideContent('link12');
 }
 
 else if(x == 'link3') {
  HideContent('link1');
  HideContent('link2');
  HideContent('link4');
  HideContent('link5');
  HideContent('link6');
  HideContent('link7');
  HideContent('link8');
  HideContent('link9');
  HideContent('link10');
  HideContent('link11');
  HideContent('link12');
 }
 
 else if(x == 'link4') {
  HideContent('link1');
  HideContent('link2');
  HideContent('link3');
  HideContent('link5');
  HideContent('link6');
  HideContent('link7');
  HideContent('link8');
  HideContent('link9');
  HideContent('link10');
  HideContent('link11');
  HideContent('link12');
 }
 
 else if(x == 'link5') {
  HideContent('link1');
  HideContent('link2');
  HideContent('link3');
  HideContent('link4');
  HideContent('link6');
  HideContent('link7');
  HideContent('link8');
  HideContent('link9');
  HideContent('link10');
  HideContent('link11');
  HideContent('link12');
 }
 
 else if(x == 'link6') {
  HideContent('link1');
  HideContent('link2');
  HideContent('link3');
  HideContent('link4');
  HideContent('link5');
  HideContent('link7');
  HideContent('link8');
  HideContent('link9');
  HideContent('link10');
  HideContent('link11');
  HideContent('link12');
 }
 
 else if(x == 'link7') {
  HideContent('link1');
  HideContent('link2');
  HideContent('link3');
  HideContent('link4');
  HideContent('link5');
  HideContent('link6');
  HideContent('link8');
  HideContent('link9');
  HideContent('link10');
  HideContent('link11');
  HideContent('link12');
 }
 
 else if(x == 'link8') {
  HideContent('link1');
  HideContent('link2');
  HideContent('link3');
  HideContent('link4');
  HideContent('link5');
  HideContent('link6');
  HideContent('link7');
  HideContent('link9');
  HideContent('link10');
  HideContent('link11');
  HideContent('link12');
 }
 
 else if(x == 'link9') {
  HideContent('link1');
  HideContent('link2');
  HideContent('link3');
  HideContent('link4');
  HideContent('link5');
  HideContent('link6');
  HideContent('link7');
  HideContent('link8');
  HideContent('link10');
  HideContent('link11');
  HideContent('link12');
 } 
 
 else if(x == 'link10') {
  HideContent('link1');
  HideContent('link2');
  HideContent('link3');
  HideContent('link4');
  HideContent('link5');
  HideContent('link6');
  HideContent('link7');
  HideContent('link8');
  HideContent('link9');
  HideContent('link11');
  HideContent('link12');
 } 
 
 else if(x == 'link11') {
  HideContent('link1');
  HideContent('link2');
  HideContent('link3');
  HideContent('link4');
  HideContent('link5');
  HideContent('link6');
  HideContent('link7');
  HideContent('link8');
  HideContent('link9');
  HideContent('link10');
  HideContent('link12');
 } 
 
 else if(x == 'link12') {
  HideContent('link1');
  HideContent('link2');
  HideContent('link3');
  HideContent('link4');
  HideContent('link5');
  HideContent('link6');
  HideContent('link7');
  HideContent('link8');
  HideContent('link9');
  HideContent('link10');
  HideContent('link11');
 } 
  
  
}