using jquery to post a value to php file but the value is not being posted (COMPANY_NAME). Code below works for multiple values but not when it's changed to post single values? Any tips?
$(function() {
    $( "#dialog:ui-dialog" ).dialog( "destroy" );
    var COMPANY_NAME = $( "#COMPANY_NAME" ),
        allFields = $( [] ).add( COMPANY_NAME ),
        tips = $( ".validateTips" );
$( "#dialog-form5" ).dialog({
        autoOpen: false,
        height: 200,
        width: 350,
        modal: true,
        buttons: {
            "ok": function() {
                var bValid = true;
                allFields.removeClass( "ui-state-error" );
                if ( bValid ) {
                    $.post("setCompany.php", {
                                                    COMPANY_NAME:$(this).val()
                     }, function(data) {
                                                    if(data=='no')
                                                    {    $("#msgbox").fadeTo(200,0.1,function()
                                                                 { 
                                                                        $(this).html(data).addClass('messageboxerrorAdd').fadeTo(900,1);
                                                                 });            
                                                    } else if (data=='wrong') {
                                                                 $("#msgbox").fadeTo(200,0.1,function()
                                                                 { 
                                                                     $(this).html("fjdhffh").addClass('messageboxerrorAdd').fadeTo(900,1);
                                                                 });
                                                    } else {
                                                                $("#msgbox").fadeTo(200,0.1,function()
                                                                 { 
                                                                       $(this).html(data).addClass('messageboxerrorAdd').fadeTo(900,1);
                                                                 });
                                                    }
                                            });
                $( this ).dialog( "close" );
                }
            },
            Cancel: function() {
                $( this ).dialog( "close" );
            }
        },
        close: function() {
            allFields.val( "" ).removeClass( "ui-state-error" );
        }
    });
});