Java scripting in SharePoint custom lists - sharepoint-2007

Question

In SharePoint lists, you are not permitted to upload files which have any kind of special characters in their file name. (For eg: file&.doc cannot be uploaded)
So I have a JavaScript code that validates the file name on submitting the list and creates a dialogue box that tells the user to rename the files before uploading and only then you can proceed.
My issue is, the code only works for 1 document, if more than 1 document is uploaded. it does not validate the second item. I need help so that I can upload n number of items and it validates eac
<Script type="text/javascript">
function PreSaveAction()
{
var attachment;
var filename="";
var fileNameSpecialCharacters = new RegExp("[~#%&*{}<>;?/+|\"]");
try {
attachment = document.getElementById("idAttachmentsTable").getElementsByTagName("span")[0].firstChild;
filename = attachment.data;
}
catch (e) {
}
if (fileNameSpecialCharacters.test(filename)) {
alert("Please remove the special characters like ~#%&*{}<>;?/+|\ from the file attachment name and reattach the file.");
return false;
}
else {
return true;
}
}
</script>

Answer 1

allow only certain files in 2007 sharepoint list
Edit: included code from comment:
<Script type="text/javascript">
function PreSaveAction()
{
var attachment;
var filename="";
try
{
attachment = document.getElementById("idAttachmentsTable")
.getElementsByTagName("span")[0]
.fi‌​rstChild;
filename = attachment.data;
}
catch (e) { }
if (!filename.match(/^(.+?\.xlsx?)$/i))
{
alert("Please attach only excel files.");
return false;
}
else
{
return true;
}
}
</script>

Answer 2

You cant loop through the list of documents? Put all the file names into a structure / Array / something and look at them all?

Answer 3

I created a modified version that will check for all attachments. The one liste here, only checks for the first attachment.
Here is mine
function chechAttachments() {
var spanTag;
var filename="";
var fileNameSpecialCharacters = new RegExp("[~#%&*{}<>;?/+|\"]");
try {
spanTag = document.getElementById("idAttachmentsTable").getElementsByTagName("span");
for (var i = 0; i < spanTag.length; i++) {
filename = spanTag[i].innerHTML;
}
}
catch (e) {
}
if (fileNameSpecialCharacters.test(filename)) {
alert('Attachments cannot contain special characters such as "[~#%&*{<>;?/+|\"]".\n\nPlease remove the special characters from the file attachment name.');
return false;
}
}