Unable to open html file in document library without saving first

Question

I've uploaded a bunch of HTML files from a DVD to a document library on our Sharepoint 2013 Enterprise server. When I try to open one of the html files it wants to save the file instead of opening it. If I choose to open the document library in Explorer
I'm able to open the html files w/o issue.
What's causing this? I know there is an option to set the file handing to permissive, but I'd rather not do that.

Answer 1

Carl,
See this link - http://sharepoint.stackexchange.com/questions/39020/how-do-i-prevent-sharepoint-from-asking-to-download-html-files-to-my-local-machi
The allowed mime types are defined in theSPWebApplication.AllowedInlineDownloadedMimeTypes
Property
Here is small PowerShell utility function I use:
function Add-SPAllowedInlineDownloadedMimeType{
[CmdLetBinding()]
param(
[Parameter(Mandatory=$true, Position=0, ValueFromPipeLine=$true)]
[Microsoft.SharePoint.PowerShell.SPWebApplicationPipeBind]$WebApplication,
[Parameter(Mandatory=$true, Position=1)]
[string]$MimeType
process{
$actualWebApp = $WebApplication.Read()
if ($actualWebApp.AllowedInlineDownloadedMimeTypes -notcontains $mimetype)
Write-Host "Adding MIME Type..."
$actualWebApp.AllowedInlineDownloadedMimeTypes.Add($mimetype)
$actualWebApp.Update()
Write-Host "Done."
} Else {
Write-Host -ForegroundColor Green "MIME type is already added."
And it can be used like this:
Add-SPAllowedInlineDownloadedMimeType -WebApplication http://mywebapp -MimeType "text/html"
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