document.observe('dom:loaded', function(event){
	var uploadFileField = $('uploadFile1');
	var uploadSubmitField = $('uploadSubmit');
	uploadFileField.observe('change', function(onChangeEvent){
		checkFileField();
	});
	var checkFileField = function() {
		var fileValue = $F(uploadFileField);
		if(fileValue) {
			uploadSubmitField.enable();
		} else {
			uploadSubmitField.disable();
		}
	};
	checkFileField();	
});