Clone with cloneNode to solve the id problem / methods deep copy and shallow copy to modify the ID

cloneNode Use the function method to solve the problem of deep replication id Repetitive questions

//        var ul1=clones(ul,true);
//        document.body.appendChild(ul1);
//         Deep copy modification id
//      function clones(sourceElem,deep,target) {
//          var elem;
//          if(sourceElem){  // If the element exists, clone it 
//              elem=sourceElem.cloneNode(deep);  //deep It is determined according to the passed in parameters 
//          }else{
//              elem=target;  // This is used in recursive callback functions 
//          }
//          if(elem.id) elem.id+=1;  // Here you are id Add a... After the element of 1
//          for(var i=0;i<elem.children.length;i++){  //elem.children   Is all child elements ,
//              clones(null,false,elem.children[i]);  // Callback function , That is, execute this row number again ,
         // The parameter passed in is null That is, no more copying , Mainly to modify the elements id
//          }
//          return elem;
//      }

A shallow copy modify ID

//        var ul=document.querySelector("ul");
      /*  var ul1=clones(ul,false);
        document.body.appendChild(ul1);
//         Shallow copy modification id
        function clones(sourceElem,deep) {
            var elem=sourceElem.cloneNode(deep);
            if(elem.id) elem.id+=1;
            return elem;
        }*/