MaxLength attribute

Is there a way to set a MaxLength number of characters allowed?

[gskinner]

For anyone else encountering this, here’s a method I wrote to enable maxLength on CodeMirror editors. It hasn’t been tested extensively, but seems to work properly with multiline copy/paste & regular editing. Just define a maxLength option on your CM instance, and add this beforeChange handler:

CMUtils.enforceMaxLength = function(cm, change) {
    var maxLength = cm.getOption("maxLength");
    if (maxLength && change.update) {
        var str = change.text.join("\n");
        var delta = str.length-(cm.indexFromPos(change.to) - cm.indexFromPos(change.from));
        if (delta <= 0) { return true; }
        delta = cm.getValue().length+delta-maxLength;
        if (delta > 0) {
            str = str.substr(0, str.length-delta);
            change.update(change.from, change.to, str.split("\n"));
        }
    }
    return true;
}

myCM.setOption("maxLength", 25);
myCM.on("beforeChange", CMUtils.enforceMaxLength);

[marijnh]

No, there isn’t. You could, if you really need this, register an onChange handler that, when the content becomes too long, undoes the current change (or simply marks the content as invalid by styling the editor differently).