Document Object Model

value Property Internet Development Index

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Retrieves the file name of the input object after the text is set by user input.

Syntax

HTML N/A
Scripting [ sValue = ] INPUT type=file.value

Possible Values

sValue String that receives the file name.

The property is read-only. The property has no default value.

Remarks

The value property returns only the file name and not the path of the file to machines outside the local machine security zone. For more information on security zones, see About URL Security Zones.
http://msdn.microsoft.com/workshop/author/dhtml/reference/properties/value_6.asp

вроде у меня то же были эти грабли.

может в случае помогут манипуляции с видимостью слоя c input (не стиль поля а стиль слоя???)