Add `valueAsNumber` support to Knockout `value` binding. More information here: http://blog.craigsworks.com/knockout-value-binding-input-number

knockout-valueAsNumber-support.js

// Add `valueAsNumber` support to `value` bindings etc
ko.selectExtensions.readValue = _.wrap(ko.selectExtensions.readValue, function(read, element) {
    var result = read.apply(this, _.rest(arguments));

    switch(ko.utils.tagNameLower(element)) {
        // For input-type `number` elements, check if it has a `valueAsNumber` property and if so, use it
        case 'input':
            if(element.type === 'number' && 'valueAsNumber' in element) {
                result = element.valueAsNumber;
            }
            break;
    }

    return result;
});