grid table固定表头

用于固定grid的表头，竖向滚动条，如图：

 

var str =  '<style>.wrapper{width:960px;margin:20px auto}.clear{clear:both}.gridView{width:100%;clear:both;margin:10px 0;border:medium none!important;border-collapse:collapse}.gridView tr td{vertical-align:top}.gridView thead tr,.footer{font:bold 11px Arial;vertical-align:middle;text-decoration:none;text-align:center}.gridView thead tr{color:#333;background:#fff;vertical-align:middle;height:25px}.gridView thead tr th{border-top:1px solid #e2e6e6;border-bottom:3px solid #e5e5e5;vertical-align:middle}.gridView thead tr a{font:bold 11px Arial,Verdana;color:#333;padding:0 0 0 10px;text-decoration:underline;vertical-align:middle}.gridView thead tr a:hover{color:#06c}.footer{height:20px;width:auto;margin:0 auto;text-align:center;padding:5px}.footer a,.footer span{color:#555;padding:2px 6px 2px 6px;border:1px solid #bcbcbc;text-decoration:none}.footer a:hover{color:#c40b17;background-color:#fff;background-image:none;border:1px solid #890812}.footer span{color:#fff;border:1px solid #890812}.grid,.gridAlternada,.gridDestacada{font:11px Arial,Verdana;text-align:left;text-align:center;vertical-align:middle}.grid:hover,.gridAlternada:hover,.gridDestacada:hover{color:#000}.grid{background-color:#fff}.gridAlternada{background-color:#eee}.gridDestacada{background-color:#ffe082;color:#333}.grid a,.gridAlternada a,.gridDestacada a{color:#384249;text-decoration:none}.grid a:hover,.gridAlternada a:hover,.gridDestacada a:hover{color:#000;text-decoration:underline}</style>'
   $('body',me.container).append(str);
   (function ($) {
    var TABLE_ID = 0;
    $.fn.freezeHeader = function (params) {

        var copiedHeader = false;

        function freezeHeader(elem) {
            var idObj = elem.attr('id') || ('tbl-' + (++TABLE_ID));
            if (elem.length > 0 && elem[0].tagName.toLowerCase() == "table") {

                var obj = {
                    id: idObj,
                    grid: elem,
                    container: null,
                    header: null,
                    divScroll: null,
                    openDivScroll: null,
                    closeDivScroll: null,
                    scroller: null
                };

                if (params && params.height !== undefined) {
                    obj.divScroll = '<div id="hdScroll' + obj.id + '" style="height: ' + params.height + '; overflow-y: scroll">';
                    obj.closeDivScroll = '</div>';
                }

                obj.header = obj.grid.find('thead');

                if (params && params.height !== undefined) {
                    if ($('#hdScroll' + obj.id).length == 0) {
                        obj.grid.wrapAll(obj.divScroll);
                    }
                }

                obj.scroller = params && params.height !== undefined
                   ? $('#hdScroll' + obj.id)
                   : $(window);

                if (params && params.scrollListenerEl !== undefined) {
                    obj.scroller = params.scrollListenerEl;
                }
                obj.scroller.on('scroll', function () {
                    if ($('#hd' + obj.id).length == 0) {
                        obj.grid.before('<div id="hd' + obj.id + '"></div>');
                    }

                    obj.container = $('#hd' + obj.id);

                    if (obj.header.offset() != null) {
                        if (limiteAlcancado(obj, params)) {
                            if (!copiedHeader) {
                                cloneHeaderRow(obj);
                                	$("#cloneHead").parent().addClass("cloneWrap").removeClass("tm-extgrid");
									$("#initHead").parent().addClass("initWrap");
                                    $("#initHead").appendTo(".cloneWrap");
									$("#cloneHead").appendTo(".initWrap");
                                copiedHeader = true;
                            }
                        }
                        else {

                            if (($(document).scrollTop() > obj.header.offset().top)) {
                                obj.container.css("position", "absolute");
                                obj.container.css("top", (obj.grid.find("tr:last").offset().top - obj.header.height()) + "px");
                                //obj.container.css("top", "0px");
                            }
                            else {
                                obj.container.css("visibility", "hidden");
                                obj.container.css("top", "0px");
                                obj.container.width(0);
                            }
                            copiedHeader = false;
                        }
                    }

                });
            }
        }

        function limiteAlcancado(obj, params) {
            if (params && (params.height !== undefined || params.scrollListenerEl !== undefined)) {
                return (obj.header.offset().top <= obj.scroller.offset().top);
            }
            else {
                return ($(document).scrollTop() > obj.header.offset().top && $(document).scrollTop() < (obj.grid.height() - obj.header.height() - obj.grid.find("tr:last").height()) + obj.header.offset().top);
            }
        }

        function cloneHeaderRow(obj) {
            obj.container.html('');
            obj.container.val('');
            var tabela = $('<table style="margin: 0 0;"></table>');
            var atributos = obj.grid.prop("attributes");

            $.each(atributos, function () {
                if (this.name != "id") {
                    tabela.attr(this.name, this.value);
                }
            });
            obj.header.attr("id","initHead");
            tabela.append('<thead id="cloneHead">' + obj.header.html() + '</thead>');

            obj.container.append(tabela);
            obj.container.width(obj.header.width());
            obj.container.height(obj.header.height);
            obj.container.find('th').each(function (index) {
                if(index==0||index==1){
                    $(this).css('width', '24px');
                }else{
                     var cellWidth = obj.grid.find('th').eq(index).width();
                	$(this).css('width', cellWidth);
                }

            });
			obj.container.css("z-index", "99");
            obj.container.css("visibility", "visible");

            if (params && params.height !== undefined) {
		if(params.offset !== undefined){
			obj.container.css("top", obj.scroller.offset().top + (params.offset.replace("px","") * 1) + "px");
		}
		else
		{
			//obj.container.css("top", obj.scroller.offset().top + "px");
		}
				
                obj.container.css("position", "absolute");
				
            } else if (params && params.scrollListenerEl!== undefined) { 
                obj.container.css("top", obj.scroller.find("thead > tr").innerHeight() + "px");
                obj.container.css("position", "absolute");
                obj.container.css("z-index", "2");
			} else if (params && params.offset !== undefined) {
			    obj.container.css("top", params.offset);
                obj.container.css("position", "fixed");
            } else {
                obj.container.css("top", "0px");
                obj.container.css("position", "fixed");
            }
        }

        return this.each(function (i, e) {
            freezeHeader($(e));
        });

    };
})(jQuery);

使用：

$("#grid .table",me.container).freezeHeader({ 'height': '300px' });