function changetabhw(layer_ref) {
 var tabbladen=["Computers1","Hardware1","Benchmarks1","Overclock1"];
 var tabcontent=["Uitleg","Computers","Hardware","nietinlijst","Benchmarks","Overclock"];
 tabie=layer_ref+'1';
 for ( var i in tabbladen )
  changetabhwcolor1(tabbladen[i],'tabuit');
 for ( var i in tabcontent )
  document.getElementById(tabcontent[i]).style.display='none';
 document.getElementById(layer_ref).style.display='block';
}

function changetabhwcolor1(layer_ref1, color) {
 var color1=  "url(http://klen.nl/images/hardware/" + color + ".PNG)";
 document.getElementById(layer_ref1).style.backgroundImage = color1;
}