Why doesn't IE see the font?

Question

css

@font-face {
    font-family: "font1";
    src: url("../fonts/font1.ttf") format("truetype");
}
@font-face {
    font-family: "font2";
    src: url("../fonts/font2.ttf") format("truetype");
}
.el1 {
    font-family: "font1", "sans-serif";
}
.el2 {
    font-family: "font2", "sans-serif";
}

For some reason, el1 is getting the font applied, but el2 is getting "sans-serif" applied. In chrome it applies to both, but in IE only to one. What the hell?

Answer 1

IE needs .eot font format
https://msdn.microsoft.com/en-us/library/ms533034(...