How to get FileName path from dialogBox?

I did it in two steps

// dialogBox just for information

app.alert({

cMsg: "select a file",

nIcon: 2

});

//open a window for select a file

// we'll never look at it so size is unimportant

var tmpDoc = app.newDoc(0,0);

// Create the Text Field

var fld = tmpDoc.addField("tmpTxt","text",0,[0,0,0,0]);

// Set up the Text field so the file dialog can be called

fld.fileSelect = true;

// Display File Open Dialog

fld.browseForFileToSubmit();

// save the selected file path to a local variable

// so it can be used later

var path_second_file = fld.value;

// Close Document without saving

tmpDoc.closeDoc(true);

console.println(path_second_file);

You probably won't be able to work with files opened from JavaScript, unless they set disclosed. Best to have the user open it, then run your script.