How to implement search function in html page

<div class="container" style="z-index: 999" id="searchDiv">
       <div class="keyword-search">
           查找：
           <input id="key" type="text" style="width: 200px;" placeholder="关键词" />
           <a href="javascript:void(0);" class="prev" onclick=&#39;wordSearch(1)&#39;><i class="c-icon"></i></a>
           <a href="javascript:void(0);" class="next" onclick=&#39;wordSearch()&#39;><i class="c-icon"></i></a>
       </div>
   </div>

<script>//搜索功能
      var oldKey0 = "";
      var index0 = -1;var oldCount0 = 0;
      var newflag = 0;
      var currentLength = 0;
      function wordSearch(flg) {
          var key = $("#key").val(); //取key值
          if (!key) {
              return; //key为空则退出
          }
          getArray();
          focusNext(flg);
      }
      function focusNext(flg) {
          if (newflag == 0) {//如果新搜索,index清零
              index0 = 0;
          }
          if (!flg) {
              if (oldCount0 != 0) {//如果还有搜索
                  if (index0 < oldCount0) {//左边如果没走完，走左边
                      focusMove(index0);
                      index0++;
                  } else if (index0 == oldCount0) {//都走完了
                      index0 = 0;
                      focusMove(index0);
                      index0++;
                  }
                  else {
                      index0 = 0;//没确定
                      focusMove(index0);
                      index0++;
                  }
              }
          } else {
              if (oldCount0 != 0) {//如果还有搜索
                  if (index0 <= oldCount0 && index0 > 0) {//左边如果没走完，走左边
                      index0--;
                      focusMove(index0);
                  } else if (index0 == 0) {//都走完了
                      index0 = oldCount0;
                      index0--
                      focusMove(index0);
                  }
              }
          }
      }
      function getArray() {
          newflag = 1;
          $(".contrast .result").removeClass("res");
          var key = $("#key").val(); //取key值
          if (!key) {
              oldKey0 = "";
              return; //key为空则退出
          }
          if (oldKey0 != key || $(".current").length != currentLength) {
              //重置
              index0 = 0;
              var index = 0;
              $(".contrast .result").each(function () {
                  $(this).replaceWith($(this).html());
              });
              pos0 = new Array();
              if ($(".contrast-wrap").hasClass("current")) {
                  currentLength = $(".current").length;
                  $(".current .contrast").each(function () {
                      $(this).html($(this).html().replace(new RegExp(key, "gm"), "<span id=&#39;result" + (index++) + "&#39; class=&#39;result&#39;>" + key + "</span>")); // 替换
                  });
              } else {
                  $(".contrast-wrap").addClass(&#39;current&#39;);
                  currentLength = $(".current").length;
                  $(".contrast").each(function () {
                      $(this).html($(this).html().replace(new RegExp(key, "gm"), "<span id=&#39;result" + (index++) + "&#39; class=&#39;result&#39;>" + key + "</span>")); // 替换
                  });
              }
              //$("#key").val(key);
              oldKey0 = key;
              //$(".contrast .result").each(function () {
              //    $(this).parents(&#39;.contrast-wrap&#39;).addClass(&#39;current&#39;);
              //    pos0.push($(this).offset().top);
              //});
              // pos0.push($(".contrast .result:eq(2)").offset().top - $(".contrast .result:eq(2)").parents(".contrast").offset().top);
              oldCount0 = $(".contrast .result").length;
              newflag = 0;
          }
      }
      function focusMove(index0) {
          $(".contrast .result:eq(" + index0 + ")").parents(&#39;.contrast-wrap&#39;).addClass(&#39;current&#39;);
          $(".contrast .result:eq(" + index0 + ")").addClass("res");
          var top = $(".contrast .result:eq(" + index0 + ")").offset().top + $(".contrast .result:eq(" + index0 + ")").parents(".contrast").scrollTop();
          var intop = top - $(".contrast .result:eq(" + index0 + ")").parents(".contrast").offset().top;
          $(".contrast .result:eq(" + index0 + ")").parents(".contrast").animate({ scrollTop: intop }, 200);
          if ($(".contrast .result:eq(" + index0 + ")").parents(".contrast").scrollTop() == 0) {
              $("html, body").animate({ scrollTop: top - 200 }, 200);
          } else {
              $("html, body").animate({ scrollTop: $(".contrast .result:eq(" + index0 + ")").parents(".contrast").offset().top - 200 }, 200);
          }
      }
      $(&#39;#key&#39;).change(function () {
          if ($(&#39;#key&#39;).val() == "") {
              index0 = 0;
              $(".contrast .result").each(function () {
                  $(this).replaceWith($(this).html());
              });
              oldKey0 = "";
          }
      });
  </script>