Problems in Opening Any File in IE 5.5?

Question

The problem is that if you run on IE, what you will see is that when the user clicks on an Excel/Word/any file to open it. The excel file opens directly in the browser. This 'emulation' of excel... in the
browser does not work. In other words, it seems to me that, in Netscape, by default, it uses an "External Viewer" to open files according to the following code (namely, files can be opened completely in a separate window!). The very same code in IE 5.5, however, uses an "Internal Viewer" to open the files (namely, only open inside a frame, not in a separate window. So half way only!). How to fix the code slightly to make it work equally well in IE 5.5?
Thanks millions! The code is attached here.
Helena
function drawFolder(leftSide)
if (browserVersion == 2) {
if (!doc.yPos)
doc.yPos=8
doc.write("<layer id='folder" + this.id + "' top=" + doc.yPos + " visibility=hiden>")
doc.write("<table ")
if (browserVersion == 1)
doc.write(" id='folder" + this.id + "' style='position:block;' ")
doc.write(" border=0 cellspacing=0 cellpadding=0>")
doc.write("<tr><td>")
doc.write(leftSide)
this.outputLink()
doc.write("<img name='folderIcon" + this.id + "' ")
doc.write("src='" + this.iconSrc+"' border=0></a>")
doc.write("</td><td valign=middle nowrap>")
if (USETEXTLINKS)
this.outputLink()
doc.write(this.desc + "</a>")
else
doc.write(this.desc)
doc.write("</td>")
doc.write("</table>")
if (browserVersion == 2) {
doc.write("</layer>")
if (browserVersion == 1) {
this.navObj = doc.all["folder"+this.id]
this.iconImg = doc.all["folderIcon"+this.id]
this.nodeImg = doc.all["nodeIcon"+this.id]
} else if (browserVersion == 2) {
this.navObj = doc.layers["folder"+this.id]
this.iconImg = this.navObj.document.images["folderIcon"+this.id]
this.nodeImg = this.navObj.document.images["nodeIcon"+this.id]
doc.yPos=doc.yPos+this.navObj.clip.height
function outputFolderLink()
if (this.hreference)
doc.write("<a href='" + this.hreference + "' TARGET=\"main\" ")
if (browserVersion > 0)
doc.write("onClick='javascript:clickOnFolder("+this.id+")'")
doc.write(">")
else
doc.write("<a>")
// doc.write("<a href='javascript:clickOnFolder("+this.id+")'>")
}

Answer 1

It's like this:
Nothing you do in the HTML or JavaScript in the browser or on the server will change what the browser does with a given file type. Any browser will do one of 3 things, in this order, with any given file:
1) Determine if the browser can display the file itself, such as for HTML files or certain image types. If so, it displays it.
2) Else, determine if there is a registered plug-in to handle that specific file type. If so, load the plug-in and give it the file.
3) Else, ask the user to save the file or select an external application to view the file, or cancel (don't download).
Using blank as a target for links does nothing to change this behavior.  All blank targets do is tell the browser to open a new browser window and "open" the link URL in that new browser window, as opposed to opening in the same window. It still goes thru the same 3 steps, regardless.
Later versions of Excel and Word will, in effect, register as plug-ins for IE, but not for Netscape. Because of this, those file types will open in Excel or Word inside the browser window, as a plug-in. This plug-in mode is still the same as the standalone version of the program. Unless there are settings in Excel or Word to unregister this plug-in mode, then there's nothing you can do. But these settings would not be changeable by the web server or web page, the user would have to change it themselves, if they can/want.
The ONLY other option is to rename the file extension (cuz IE often ignores mime-type and uses extension) and use "application/octet-stream" as the mime-type of the file, from the server. The effect is that the browser will ask the user to save it, where they would have to rename it to the right extension.
My recommended solution:
I'm assuming that foremost, you don't want the user to have to leave the page the links are on. This is why you use the _blank target.  This will pass the file or link to a new browser window.  Beyond that, you have no other control what happens.  Are you assuming/enforcing somehow that all users are using IE, and they have Excel or Word installed in the first place?  Or that they are newer versions which even have this plug-in capability.  There's no true way to enforce what I think you think you want to do.