This is a colModel search options. In order to do this you will need to set this on every item in colModel.
If you want all the fields to have this you can use colModel templates.

Everything is described in the docs.

You can start from here

Regards

How I can determine wich operators want to show in a "multisearch navigator"?. I want to show only eq, ew, cn and bw. I have the code below. I tryed adding {sopt:['cn','bw','eq','ew']} at the end but doesnt works. Can anybody help me?

$("#list").jqGrid('navGrid','#pager', { view: false, del: false, add: false, edit: false },{},{},{},{multipleSearch:true, closeAfterSearch: true});

Thank you,

LTLG