IE only shipped with JavaScript and VBScript built-in. Other language engines could be installed (Perl and Python for example), but realistically nobody would w

IE only shipped with JavaScript and VBScript built-in. Other language engines could be installed (Perl and Python for example), but realistically nobody would write client-side code in a language which required a visitor to install support for it. VBScript was the only viable contender, but it never really had any compelling advantages compared to JavaScript. JavaScript is often criticized for quirky design and syntax, but if anything VBScript was worse. Also the pluggable script engines were based on COM, so only worked on Windows. I don't think VBScript was ever supported in IE for Mac. I don't think Microsoft ever saw a strategic advantage to promoting alternative languages on the web. Otherwise they would have done a lot more.