add dynamic element into array

 var x = 0;
    var counter = 0 ;

    $(function () {
        $('#addBtn').click(function () {

                        x++;

                       if (counter < 5) {
                counter++;
                $('#content').append('<input type="text" id="mytxt' + x + '">');
                $('#content').append('<input type="button" id="removeBtn' + x + '" value="Remove" onclick="removeRow(' + x + ')" />');
                $('#content').append('<div id="br' + x + '"/><开发者_如何学JAVA;/div>');



            } else {
                alert("you cannot added more than 5 element");
            }


        }
        );



    });




    function removeRow(index) {
        $('#mytxt' + index).remove();
        $('#removeBtn' + index).remove();
        $('#br' + index).remove();
        counter--;
           alert(counter);

    }

this is my function to create dynamic button, when i clicked "addBtn", new element will be created and id start with 1,eg: mytxt1, and when i clicked "removeBtn" and "addBtn" again,the id will become mytxt2, the result is out of my expected, what i want is when i clicked "removeBtn" and "addBtn" ,the id will start from 1 again,but not 2

new updated

that is one of my question also, if i added more element let said 4 element,the id i get will be mytxt1,mytxt2,mytxt3 and mytxt4, and if i remove mytxt2, the next element i added will become mytxt1,mytxt3,mytxt4,and mytxt5, and this is not what i want,what i want is mytxt1,mytxt2,mytxt3 and mytxt4

Could it be that none of the Id's match up?

As close as I can tell by your code we have:

#myTxt1 == #my1 
#removeBtn1 == #but1 
#br1 == #div1

The following (untested) code keeps track of which indexes have been used, and allows reuse of indexes formerly associated with removed items. Note that the user could remove items in any order; this code reuses lower indexes first.

var maxElements = 5,
    indexes = [];

$(function () {
   $('#addBtn').click(function () {
      // look for a false or undefined index in the array
      // note: index numbers will start at 1 as in the question
      for (var x=1; x <= maxElements; x++) {
         if (!indexes[x]) {
            // found a currently unused index, so use it, and mark as used
            indexes[x] = true;

            $('#content').append('<input type="text" id="mytxt' + x + '">');
            $('#content').append('<input type="button" id="removeBtn' + x 
                        + '" value="Remove" onclick="removeRow(' + x + ')" />');
            $('#content').append('<div id="br' + x + '"/></div>');

            return;
         }
      }

      // no unused index was found
      alert("You cannot added more than " + maxElements + " elements.");
   });
});

function removeRow(index) {
   $('#removeBtn' + index).remove();
   $('#mytxt' + index).remove();
   $('#br' + index).remove();

   // mark index as not used
   indexes[index] = false;
}

EDIT: Note, I kept this as similar to your starting code as I could, but I removed the counter variable entirely because my code doesn't use it - obviously you can put it back (with corresponding counter++ and counter-- in the appropriate places) if you want instant access to the current count of elements.

Try removing function wrapper from your code

$(function () {  
// 
 });