成功/失败后插入语句后的警报窗口

Question

我有一个对话框，可以在提交时向数据库添加一行。但是，如果插入有错误，我想要显示一个警告窗口，以便用户知道它不起作用。我尝试在我的php中使用javascript但是返回了一个错误，每当我尝试这个时，这就是我总是得到的错误：Uncaught SyntaxError: Unexpected token E in JSON。

如何解决此问题并在提交时显示警告？

这是我原来的Insert.php代码的样子......

<?php

  $MR_ID = $_POST['MR_ID'];
  $Supp_ID = $_POST['Supp_ID'];

  $host="xxxxxxxxx"; 
  $dbName="xxxx"; 
  $dbUser="xxxxxxxxxxx"; 
  $dbPass="xxxxxxxxx";

  $pdo = new PDO("sqlsrv:server=".$host.";Database=".$dbName, $dbUser, $dbPass);

  $sql = "INSERT INTO Stage_Rebate_Index (MR_ID, Supp_ID) VALUES (?, ?)";
  $stmt = $pdo->prepare($sql);
  $result = $stmt->execute(array($MR_ID, $Supp_ID));
  echo json_encode($result);

?>

编辑：

JavaScript代码：

// ----- Dialog Box for adding mr id and supplier id -----

$( function() {


    $("#insertButton").on('click', function(e){
    e.preventDefault();
  });   

    var dialog, form,

      mr_id_dialog = $( "#mr_id_dialog" ),
      supplier_id = $( "#supplier_id" ),
      allFields = $( [] ).add( mr_id_dialog ).add( supplier_id ),
      tips = $( ".validateTips" );
  console.log(allFields);

    function updateTips( t ) {
      tips
        .text( t )
        .addClass( "ui-state-highlight" );
      setTimeout(function() {
        tips.removeClass( "ui-state-highlight", 1500 );
      }, 500 );
    }

    function checkRegexp( o, regexp, n ) {
      if ( !( regexp.test( o.val() ) ) ) {
        o.addClass( "ui-state-error" );
        updateTips( n );
        return false;
      } else {
        return true;
      }
    }

   function addVendor() {
      var valid = true;
      allFields.removeClass( "ui-state-error" );
// ----- Validation for each input in add row dialog box -----
      //valid = valid && checkRegexp( mr_id_dialog, /^(0|[1-9][0-9]*)$/, "Please enter a valid MR ID" );
      valid = valid && checkRegexp( supplier_id, /^(0|[1-9][0-9]*)$/, "Please enter a valid Supplier ID" );
      console.log(allFields);
      if ( valid ) {
        var $tr = $( "#index_table tbody tr" ).eq(0).clone();
        var dict = {};
        var errors = "";
        $.each(allFields, function(){
          $tr.find('.' + $(this).attr('id')).html( $(this).val()+"-"+supplier_id );
          var type = $(this).attr('id');
          var value = $(this).val();
          console.log(type + " : " + value);
          // ----- Switch statement that provides validation for each table cell -----
          switch (type) {
            case "mr_id_dialog":
                dict["MR_ID"] = parseInt(value);
                console.log(dict['MR_ID']);
              break;
            case "supplier_id":
                dict["Supp_ID"] = value;
              break;
            }
        });
        $( "#index_table tbody" ).append($tr);
        dialog.dialog( "close" );
        console.log(dict);

        var request = $.ajax({
          type: "POST",
          url: "insert.php",
          data: dict
        });

        request.done(function (response, textStatus, jqXHR){
          if(JSON.parse(response) == true){
            console.log("row inserted");
          } else {
            console.log("row failed to insert");
            console.log(response);
          }
        });

        // Callback handler that will be called on failure
        request.fail(function (jqXHR, textStatus, errorThrown){
            console.error(
                "The following error occurred: "+
                textStatus, errorThrown
            );
        });

        // Callback handler that will be called regardless
        // if the request failed or succeeded
        request.always(function () {

        });


      }
      return valid;
    }

    var dialog = $( "#dialog-form" ).dialog({
      autoOpen: false,
      height: 400,
      width: 350,
      modal: true,
      buttons: {
        "Add Supplier ID": addVendor,
        Cancel: function() {
          dialog.dialog( "close" );
        }
      },
      close: function() {
        form[ 0 ].reset();
        allFields.removeClass( "ui-state-error" );
      }
    });

    form = dialog.find( "form" ).on( "submit", function( event ) {
      event.preventDefault();
      addVendor();
    });

    $( "#insertButton" ).button().on( "click", function() {
      dialog.dialog({
          position: ['center', 'top'],
          show: 'blind',
          hide: 'blind'
      });
      dialog.dialog("open");
    });
});