Combo filter in header, with checkbox

I am using a #select_filter in the header, it works well for me. But I need to select multiple values in the drop down list. How can we include checkboxes at this place.
How can that be done? Please provide a sample code for the same.

Below is the code snippet of the js file that I am using currently.

SupportToolBody.js

mygrid.setHeader(“Name,Support Contract,Support Level,Product,#cspan,#cspan,#cspan,#cspan,#cspan,#cspan”);
mygrid.attachHeader(“#text_filter,End Date,#select_filter,Maintenance Status,Version Smart Num,Base Smart Num, Product Version Status,Solution,Support Only,CompanyIntegrationId”);
mygrid.setColTypes(“tree,ro,ro,ro,ro,ro,ro,ro,ro,ro”);
mygrid.setColSorting(“str,str,str,str,str,str,str,str,str,str”);
mygrid.enableTreeCellEdit(false);
mygrid.enableSmartXMLParsing(true);
mygrid.setColumnHidden(colSupportOnly,true);
mygrid.setColumnHidden(colCompIntId,true);
mygrid.enableTooltips(“true,false,false,false,false,false,false,false”);
mygrid.init();
mygrid.attachEvent(“onXLS”,func_loadstart);
mygrid.attachEvent(“onXLE”,func_loaddone);
//enable block selection
mygrid.enableBlockSelection(true);


Unfortunately such feature is not available using the select_filter.
You will have to create your own custom filter.
Here you can find a tutorial:
docs.dhtmlx.com/doku.php?id=dhtm … of_filters

I need to attach my custom HTML element in header. Please suggest how can this be done.
Below are the snapshots of code and its result.




Here you can find tutorial about adding custom content in the header/footer of the grid:
docs.dhtmlx.com/doku.php?id=dhtm … ader_extra