How to force users to enter Four Numbers ONLY in inputbox

[loveguy1977]

Hi dears,
I need your help to force users to enter FOUR NUMMBERS ONLY into inputbox. I mean "0548" or "1548" and so on.

More or less than four numbers is not acceptiable.

Note that I i don't want the user leave the inputbox until he enter four numbers even if he/she press No then return bigging of the inputbox.

Thanks in advance

[jproffer]

Asked and answered on MrExcel.com :)

[lucas]

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Why crossposting without providing a link is inconsiderate to those who are here to help you. (http://www.excelguru.ca/node/7)