The filter is stored in a JSON similar to the following 

{
  "groupOp": "AND",
  "rules": [
    {
      "field": "status",
      "op": "cn",
      "data": "Open"
    },
    {
      "field": "comments",
      "op": "cn",
      "data": "Customer"
    }
  ]
}

To obtain the above filter from a search, one can use the following script

$('#TABLE NAME').getGridParam("postData").filters;