After a first half of few real chances in wet conditions, the home side took the lead just after the hour through Tom Bradbrook’s header.
But Town kept going and after John-Lewis was brought down inside the penalty area six minutes from time, he got up to equalise from the spot.
Dartford were reduced to 10 men after Nathan Collier was sent off for the challenge that resulted in the penalty and afterwards, the Mariners pushed for a winner.
But that crucial second goal was not to come and both sides were forced to settle for a share of the points.
Two changes were made to the Grimsby side after the 1-0 defeat by Southport in midweek, with Craig Disley and Patrick McLaughlin coming in for Craig Clay and Scott Neilson.
James McKeown started in goal, with Danny Parslow, Aristote Nsiala, Shaun Pearson and Carl Magnay forming the defence.
The midfielders were Jack Mackreth, Disley, Scott Brown and McLaughlin, with John-Lewis and Ross Hannah again selected as the strike partnership.
Clay and Neilson were joined on the bench by Paul Bignot, Rhys Oates and Paul Walker.
Dartford included former Town winger Peter Sweeney in their starting XI, with the hosts looking to make it three games unbeaten since a 2-1 defeat against Forest Green on September 20.
An early cross from Hannah was headed away from danger, before Danny Harris was shown the first yellow card of the game within the opening three minutes for a late challenge on Parslow.
A foul on John-Lewis gave Town a free kick in a good position on seven minutes but from it, Hannah shot wide.
A passage of Grimsby possession led to Mackreth hitting a cross-shot off-target as Town continued to do most of the attacking in the early stages.
Then, the Mariners went close when John-Lewis chested the ball down for Hannah and the striker hit a dipping volley from long range which beat home keeper Jason Brown but drifted just wide.
Magnay was booked for a foul on Lee Burns on 17 minutes, then the home side could have taken the lead when the ball was played into the Town box but no attacker could get on the end of it.
Burns was forced off after the challenge from Magnay, who caught him in the ribs after a sliding tackle, with Ryan Hayes coming on.
A Grimsby corner then saw Brown find the head of Hannah but the striker could not direct it towards goal and the ball went out for a goal kick.
Mackreth failed to test keeper Brown with a shot that went wide on 25 minutes and the former Macclesfield winger was the next to go into the referee’s notebook three minutes later. The resulting free kick after his foul led to Max Cornhill heading over the bar.
A Dartford corner from the left led to captain Elliot Bradbrook hitting the bar with a shot from inside the box, before the Mariners eventually cleared.
Both sides were finding the wet conditions difficult, with the game being scrappy as a result as neither keeper had been called into any serious action so far.
Disley needed treatment after being caught late with a challenge but he was passed fit to play on.
A Magnay cross led to Disley aiming to deflect a Hannah shot towards goal, before the ball broke for McLaughlin but his shot was stopped by Brown in the Dartford goal.
Hannah’s cross three minutes before the break was deflected behind for a corner but Brown’s near-post delivery was headed away and McLaughlin then conceded a free kick for a foul on substitute Hayes.
Three added minutes were played at the end of the first half and the fourth booking of the game went to Tom Bender for a foul on Mackreth. The resulting free kick from McKeown was headed on by Disley for Hannah to fire over the bar.
That proved to be the last chance of the half, meaning the game remained goalless at the interval.
No further changes were made before the restart and a cross from Harris three minutes in was headed away by Nsiala as the home side were the first to get the ball into the danger zone.
A free kick for a foul by John-Lewis came to nothing, before another free kick from Sweeney on the right also filed to cause problems.
At the other end, a Town free kick was half-cleared and the Mariners worked the ball back for Hannah to cross but Disley was just beaten to the ball in front of goal.
A tussle between Tom Bradbrook and Nsiala earned both a booking, before a Dartford penalty shout was ignored by referee Christopher Powell.
Dartford took the lead on the hour, when a deep cross towards the far post found TOM BRADBROOK and his header hit the net, despite the efforts of Nsiala to keep it out.
Hayes was shown the yellow card for kicking Magnay soon after the goal and the left-back was well off-target with Town’s next attempt at goal.
Neilson replaced Mackreth as Grimsby boss Paul Hurst made his first substitution with 25 minutes to go.
A header from Tom Bradbrook was straight at McKeown four minutes later, before John-Lewis tried to work some space for a shot at the other end.
Town managed to put a spell of possession together soon afterwards but were unable to turn it into a chance in font of goal.
The Mariners then won a corner after a shot from Magnay was saved, although Neilson’s low flag-kick was comfortably cleared.
John-Lewis then hit a volley over the bar after being picked out by Neilson, before Luke Daley replaced Harris for the hosts.
A Town corner on 77 minutes led to a header from Pearson being cleared off the line and when the ball eventually fell for Nsiala, he sent it over the bar.
Oates came on for Hannah in the Town attack and shortly afterwards, a Dartford corner had to be cleared off the line.
The Barnsley loanee fired a shot over the bar after Neilson had taken the ball into the box with 10 minutes left on the clock.
The Mariners were given an opportunity to get themselves back into the game when Oates charged a clearance down and John-Lewis was brought down inside the box by last man Nathan Collier, who was sent off. JOHN-LEWIS stepped up to take the penalty and fired it into the top corner for 1-1.
Neilson hit a shot wide from the edge of the box as the Grimsby revival continued, before two away corners in quick succession failed to trouble the Dartford keeper.
Town were now pushing for a winner and they almost had it through a header from Disley but he was denied by Brown, at the expense of a corner.
Five added minutes were signalled by the fourth official, with Grimsby on the up as they looked to snatch all three points.
But they still had some defending to do at the other end, as Pearson headed a free kick away for a corner, which was dealt with.
That was the last action of the game, meaning both sides had to settle for a share of the spoils.
Town are next in action on Tuesday, when Altrincham visit Blundell Park.