newarr[index] = thisid; should just be
newarr = thisid;.
but then again i dont even think i understand what you want to do.
why are you working from the .click handler?
on each click you set newclass to the clicked item and add it to the array. but you also remove the newclass from the siblings, so the previously clicked items will lose the newclass again... so in newarr only the last clicked item will have newclass