text: $(function () {
      $("#background").css({'width':$(window).width(),'height':$(window).height()})
  })
  
  
  //切换内容
  function set(id) {
  
      if (id == 1){
          document.getElementById("mid_bb_a").style.display = "block";
          document.getElementById("mid_bb_b").style.display = "none";
          document.getElementById("mid_bb_c").style.display = "none";
          document.getElementById("mid_bb_d").style.display = "none";
  
          document.getElementById("mid_aa_img1").style.display = "block";
          document.getElementById("mid_aa_img2").style.display = "none";
          document.getElementById("mid_aa_img3").style.display = "none";
          document.getElementById("mid_aa_img4").style.display = "none";
      }
      if (id == 2){
          document.getElementById("mid_bb_a").style.display = "none";
          document.getElementById("mid_bb_b").style.display = "block";
          document.getElementById("mid_bb_c").style.display = "none";
          document.getElementById("mid_bb_d").style.display = "none";
  
          document.getElementById("mid_aa_img1").style.display = "none";
          document.getElementById("mid_aa_img2").style.display = "block";
          document.getElementById("mid_aa_img3").style.display = "none";
          document.getElementById("mid_aa_img4").style.display = "none";
      }
      if (id == 3){
          document.getElementById("mid_bb_a").style.display = "none";
          document.getElementById("mid_bb_b").style.display = "none";
          document.getElementById("mid_bb_c").style.display = "block";
          document.getElementById("mid_bb_d").style.display = "none";
  
          document.getElementById("mid_aa_img1").style.display = "none";
          document.getElementById("mid_aa_img2").style.display = "none";
          document.getElementById("mid_aa_img3").style.display = "block";
          document.getElementById("mid_aa_img4").style.display = "none";
      }
      if (id == 4){
          document.getElementById("mid_bb_a").style.display = "none";
          document.getElementById("mid_bb_b").style.display = "none";
          document.getElementById("mid_bb_c").style.display = "none";
          document.getElementById("mid_bb_d").style.display = "block";
  
          document.getElementById("mid_aa_img1").style.display = "none";
          document.getElementById("mid_aa_img2").style.display = "none";
          document.getElementById("mid_aa_img3").style.display = "none";
          document.getElementById("mid_aa_img4").style.display = "block";
      }
  }
  
  
  
  
  
  