There were home wins for Stevenage and Tranmere Rovers while Sheffield United were held by Colchester United and Yeovil and Scunthorpe United played out a 2-2 draw on Tuesday evening.
Second-placed Sheffield United went ahead at Colchester through Will Hoskins in the first half before Keith Gillespie equalised for the home side 11 minutes after the interval.
The point sees Danny Wilson's men move two points clear of local rivals Sheffield Wednesday in third while Charlton are now nine ahead at the top.
Stevenage strengthened their playoff hopes thanks to Lawrie Wilson's 90th minute header against Oldham Athletic. Three points for Gary Smith's men mean they are two points off the playoffs in eighth.
Goals from Enoch Showunmi and Andy Robinson for Tranmere cancelled out Graham Cummins early strike for Preston to move Rovers seven points clear of the drop zone.
At Huish Park Jon Parkin scored a 94th minute equaliser for visiting Scunthorpe to earn the Irons a precious point after strikes from Jonathan Franks and Gavin Williams seemed to have given Yeovil victory.
