How to disable multiple upload button for Document List in Sharepoint 2010

1. Open upload.aspx file in Visual Studio, upload.aspx file found this file in "14\TEMPLATE\LAYOUTS" folder.
2. Search for "if (hideLink)" statement , you have to set hideLink variable to true for hiding the multiple upload button.

hideLink =yourJavaScriptFunction();

if ( hideLink)

...
3. replace yourJavaScriptFunction with your javascript function which returns bool value.