Removing white layer which appears on floor after spilling water
Assuming it is indeed laminate flooring. 

To take the stain out:
Toothpaste lightly rubbed on the stain is often suggested. Another one  is vinegar mixed with a bit of olive oil.

If the stain does not come out - Using Tea to Mask White Stains on Laminate Flooring.

Take two tea bags, put in a cup, just about cover them with boiling water, leave it to cool, then put the liquid on the white marks on the laminate flooring. Just rub in gently with your fingers, leave for about half an hour, then remove some of the liquid with a tissue to check the result. The liquid (tea, which has tannin in - the colour agent) will have started to dry out. If the white mark is still evident leave for another 15 mins, then just wipe the area clean with a soft damp cloth. This worked for my laminate floor and it is now fully restored.