Right now we use codemirror's JavaScript mode on the website but there's a JSX mode now so we should start using that instead.

d.mover = elt("div", [elt("div", [d.lineSpace], "CodeMirror-lines")], null, "position: relative");
    
    d.sizer = elt("div", [d.mover], "CodeMirror-sizer");
    
    d.heightForcer = elt("div", null, null, "position: absolute; height: " + scrollerCutOff + "px; width: 1px;");
    
    d.gutters = elt("div", null, "CodeMirror-gutters");
    d.lineGutter = null;
    
    d.scroller = elt("div", [d.sizer, d.heightForcer, d.gutters], "CodeMirror-scroll");
    d.scroller.setAttribute("tabIndex", "-1");
    
    d.wrapper = elt("div", [d.inputDiv, d.scrollbarH, d.scrollbarV,
                            d.scrollbarFiller, d.gutterFiller, d.scroller], "CodeMirror");
    
    if (ie_lt8) { d.gutters.style.zIndex = -1; d.scroller.style.paddingRight = 0; }
    if (place.appendChild) place.appendChild(d.wrapper); else place(d.wrapper);
    
    if (ios) input.style.width = "0px";
    if (!webkit) d.scroller.draggable = true;
    
    if (khtml) { d.inputDiv.style.height = "1px"; d.inputDiv.style.position = "absolute"; }
    
    else if (ie_lt8) d.scrollbarH.style.minWidth = d.scrollbarV.style.minWidth = "18px";
    
    d.viewOffset = d.lastSizeC = 0;
    d.showingFrom = d.showingTo = docStart;