function Insert()
{
var ArrayVal=['A','B','C']
  for(var i=0 ; i<3 ; i++ )
    {
      $.ajax({
                url: "URL",
                type: "POST",
                data:  JSON.stringify({ '__metadata': { 'type': 'SP.Data.TeamListItem' },
                     'Title': ArrayVal[i]}),
                headers: {
                    "accept": "application/json;odata=verbose",
                    "content-type":"application/json;odata=verbose",
                    "X-RequestDigest": $("#__REQUESTDIGEST").val()
                },
                success: function(d) {
                alert("Inserted");
                },
                error: function ( xhr, status, error) {
                    alert("error");
                }
        });
    }
}

var promises=[];

    $(document).ready(function(){
    $("#DelButton").click(function(){

    for (var i=1; i<5; i++){
            /* $.ajax returns a promise*/
            var request=  $.ajax({
            url: "URL",
            type: "DELETE",
            headers: {
                "accept": "application/json;odata=verbose",
                "X-RequestDigest": $("#__REQUESTDIGEST").val(),
                "If-Match": "*"
            },
            success: function (data) {
               alert("success");
            },
            error: function (error) {
                alert(JSON.stringify(error));
            }
        });
           promises.push( request);
    }
     $.when.apply(null, promises).done(function(){
           alert('All done')
      })});});

var promises1=[];
var promises2=[];
var promises3=[];
var request1;
var request2;
var request3;
$(document).ready(function () {
$('#test').click(function(){
var idCount=0;
if(idCount!=0)
        {
    request3 = $.ajax({
                url:"URL",
                type: "GET",
                headers:    {
                            "accept": "application/json;odata=verbose",
                            },
                success: function (data) {
                        for(var s=0;s<dlength;s++)
                            {
                                if(data.d.results[s].Is_x0020_Manager==true)
                                    {                                                                   managerarray[m]=data.d.results[s].Title;
                                    }
                            }
for(var k=0;k<dlength;k++)
{
for(var l=0;l<managerarray.length;l++)
        {

        if(data.d.results[k].Title==managerarray[l])
        {
            managername=managerarray[l+1];
        }
        }

request2 = $.ajax({
        url: "URL",
        type: "POST",
        data:  JSON.stringify({ '__metadata': { 'type': 'SP.Data.XYZListItem' },
             'Title': data.d.results[k].Title}),
        headers: {
            "accept": "application/json;odata=verbose",
            "content-type":"application/json;odata=verbose",
            "X-RequestDigest": $("#__REQUESTDIGEST").val()
        },
        success: function(d) {
        alert("Inserted to teams list");
        },
        error: function ( xhr, status, error) {
        }
});
 promises2.push( request2);
}
                    },
                        error: function ( xhr, status, error) {
                            }
                    });
promises3.push( request3);
        }

$.when.apply(null, promises2).done(function(){
       alert('Promises2')
  })
$.when.apply(null, promises3).done(function(){
       alert('Promises3')
  })
})
});

async : false

request2 = $.ajax({
        async: false,
        url: "URL",
        type: "POST",
        data:  JSON.stringify({ '__metadata': { 'type': 'SP.Data.XYZListItem' },
             'Title': data.d.results[k].Title}),
        headers: {
            "accept": "application/json;odata=verbose",
            "content-type":"application/json;odata=verbose",
            "X-RequestDigest": $("#__REQUESTDIGEST").val()
        },
        success: function(d) {
        alert("Inserted to teams list");
        },
        error: function ( xhr, status, error) {
        }
});