How to solve this issue: Autocomplete cannot accept special characters?

Hi all,
i have an autocomplete in my web page, but when i type some special characters such as \  or  '
it will popup error.

how to solve this?  the autocomplete should accept special characters because user may type any thing in the text area.

thanks a lot

<script type="text/javascript">
        $(function () {
            

            $("#tbComm").autocomplete({
                source: function (request, response) {
                    $.ajax({
                        url: "Comments.asmx/FetchCommentary",
                        data: "{'comm': '" + request.term +  "'}",
                        dataType: "json",
                        type: "POST",
                        contentType: "application/json; charset=utf-8",
                        dataFilter: function (data) { return data; },
                        success: function (data) {
                            response($.map(data.d, function (item) {
                                return {
                                    value: item.Commentary
                                }
                            }))
                        },
                        error: function (XMLHttpRequest, textStatus, errorThrown) {
                            alert(textStatus);
                        }
                    });
                }
            });
        });
*********************
<div class="ui-widget">
                        <label for="tbComm" style="text-align:left;" >Comments: 
</label><br />
                        <asp:TextBox ID="tbComm" class="field_item" runat="server" TextMode="MultiLine" 
                            Height="120px" Width="377px"></asp:TextBox>
                        
                        <br />
                        
                    </div>
*****************************
[WebMethod]
    public List<Commentary> FetchCommentary(string comm)
    {
        var comment = new Commentary();        
        var fetchComm = comment.GetCommentary()
        .Where(m => m.Commentary.ToLower().StartsWith(comm.ToLower()));
        return fetchComm.ToList();
    }

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