function choosebg(cas, resol) {
  var resul;
  switch (cas) {
  case "general": resul = bg(resol);
    break;
  case "index"  : resul = bgindex(resol);
    break;
  case "eg"     : resul = bgeg(resol);
    break;
  case "sts"    : resul = bgsts(resol);
    break;
  case "stic"   : resul = bgstic(resol);
    break;
  case "sti"    : resul = bgsti(resol);
    break;
  }
  return resul;
}

function bg(r) {
  var lestyle;
  switch (r) {
  case 800  : lestyle="<style type=\"text/css\" media=\"screen\">body {background-image:url('images/background1.jpg');}</style>";
    break;
  case 1024 : lestyle="<style type=\"text/css\" media=\"screen\">body {background-image:url('images/background2.jpg');}</style>";
    break;
  case 1152 : lestyle="<style type=\"text/css\" media=\"screen\">body {background-image:url('images/background3.jpg');}</style>";
    break;
  case 1280 : lestyle="<style type=\"text/css\" media=\"screen\">body {background-image:url('images/background4.jpg');}</style>";
    break;
  default   : lestyle="<style type=\"text/css\" media=\"screen\">body {background-image:url('images/background2.jpg');}</style>";
    break;
  }
  return lestyle;
}
function bgindex(r) {
  var lestyle;
  switch (r) {
  case 800  : lestyle="<style type=\"text/css\" media=\"screen\">body {background-image:url('images/index1.jpg');}</style>";
    break;
  case 1024 : lestyle="<style type=\"text/css\" media=\"screen\">body {background-image:url('images/index2.jpg');}</style>";
    break;
  case 1152 : lestyle="<style type=\"text/css\" media=\"screen\">body {background-image:url('images/index3.jpg');}</style>";
    break;
  case 1280 : lestyle="<style type=\"text/css\" media=\"screen\">body {background-image:url('images/index4.jpg');}</style>";
    break;
  default   : lestyle="<style type=\"text/css\" media=\"screen\">body {background-image:url('images/index2.jpg');}</style>";
    break;
  }
  return lestyle;
}

function bgeg(r) {
  var lestyle;
  switch (r) {
  case 800  : lestyle="<style type=\"text/css\" media=\"screen\">body {background-image:url('images/eg1.jpg');}</style>";
    break;
  case 1024 : lestyle="<style type=\"text/css\" media=\"screen\">body {background-image:url('images/eg2.jpg');}</style>";
    break;
  case 1152 : lestyle="<style type=\"text/css\" media=\"screen\">body {background-image:url('images/eg3.jpg');}</style>";
    break;
  case 1280 : lestyle="<style type=\"text/css\" media=\"screen\">body {background-image:url('images/eg4.jpg');}</style>";
    break;
  default   : lestyle="<style type=\"text/css\" media=\"screen\">body {background-image:url('images/eg2.jpg');}</style>";
    break;
  }
  return lestyle;
}
function bgsts(r) {
  var lestyle;
  switch (r) {
  case 800  : lestyle="<style type=\"text/css\" media=\"screen\">body {background-image:url('images/sts1.jpg');}</style>";
    break;
  case 1024 : lestyle="<style type=\"text/css\" media=\"screen\">body {background-image:url('images/sts2.jpg');}</style>";
    break;
  case 1152 : lestyle="<style type=\"text/css\" media=\"screen\">body {background-image:url('images/sts3.jpg');}</style>";
    break;
  case 1280 : lestyle="<style type=\"text/css\" media=\"screen\">body {background-image:url('images/sts4.jpg');}</style>";
    break;
  default   : lestyle="<style type=\"text/css\" media=\"screen\">body {background-image:url('images/sts2.jpg');}</style>";
    break;
  }
  return lestyle;
}
function bgstic(r) {
  var lestyle;
  switch (r) {
  case 800  : lestyle="<style type=\"text/css\" media=\"screen\">body {background-image:url('images/stic1.jpg');}</style>";
    break;
  case 1024 : lestyle="<style type=\"text/css\" media=\"screen\">body {background-image:url('images/stic2.jpg');}</style>";
    break;
  case 1152 : lestyle="<style type=\"text/css\" media=\"screen\">body {background-image:url('images/stic3.jpg');}</style>";
    break;
  case 1280 : lestyle="<style type=\"text/css\" media=\"screen\">body {background-image:url('images/stic4.jpg');}</style>";
    break;
  default   : lestyle="<style type=\"text/css\" media=\"screen\">body {background-image:url('images/stic2.jpg');}</style>";
    break;
  }
  return lestyle;
}
function bgsti(r) {
  var lestyle;
  switch (r) {
  case 800  : lestyle="<style type=\"text/css\" media=\"screen\">body {background-image:url('images/sti1.jpg');}</style>";
    break;
  case 1024 : lestyle="<style type=\"text/css\" media=\"screen\">body {background-image:url('images/sti2.jpg');}</style>";
    break;
  case 1152 : lestyle="<style type=\"text/css\" media=\"screen\">body {background-image:url('images/sti3.jpg');}</style>";
    break;
  case 1280 : lestyle="<style type=\"text/css\" media=\"screen\">body {background-image:url('images/sti4.jpg');}</style>";
    break;
  default   : lestyle="<style type=\"text/css\" media=\"screen\">body {background-image:url('images/sti2.jpg');}</style>";
    break;
  }
  return lestyle;
}