You can write custom php code to update time_consumed in on_insert function callback OR on_after_insert.
Refer http://www.phpgrid.org/docs/#Grid_Events

Hello Abu,

I have tried with this basic funtion, it's a timer:

<script>
// Set the date we're counting down to
var countDownDate = new Date("Jan 5, 2018 15:37:25").getTime();

// Update the count down every 1 second
var x = setInterval(function() {

// Get todays date and time
var now = new Date().getTime();

// Find the distance between now an the count down date
var distance = countDownDate – now;

// Time calculations for days, hours, minutes and seconds
var days = Math.floor(distance / (1000 * 60 * 60 * 24));
var hours = Math.floor((distance % (1000 * 60 * 60 * 24)) / (1000 * 60 * 60));
var minutes = Math.floor((distance % (1000 * 60 * 60)) / (1000 * 60));
var seconds = Math.floor((distance % (1000 * 60)) / 1000);

// Display the result in the element with id="demo"
document.getElementById("demo").innerHTML = hours + "h "
+ minutes + "m " + seconds + "s ";

// If the count down is finished, write some text
if (distance < 0) {
clearInterval(x);
document.getElementById("demo").innerHTML = "EXPIRED";
}
}, 1000);

</script>

Then in grid col:

# Custom made column to show extra buttons, must have default value as it's not db driven
$col = array();
$col["title"] = "Timer";
$col["name"] = "more_icons";
$col["fixed"] = true;
$col["width"] = "85";
$col["align"] = "center";
$col["search"] = false;
$col["sortable"] = false;
# no new line in this html, only space. otherwise it may break ui of grid
$buttons_html .= '<p id="demo"></p>';
$col["default"] = $buttons_html;
$sales[] = $col;

This is working in first row, other rows are empty; otherwise the countDownDate Var is based in a Date of Row so:

var rowid = jQuery("#list1").jqGrid("getGridParam","selrow");

var row = $("#list1").getRowData(rowid);

var date= row["date"];

Thank you by your help!