var nonLinearSlider = document.getElementById('nonlinear');

noUiSlider.create(nonLinearSlider, {
    connect: true,
    behaviour: 'tap',
    start: [500, 4000],
    range: {
        // Starting at 500, step the value by 500,
        // until 4000 is reached. From there, step by 1000.
        'min': [0],
        '10%': [500, 500],
        '50%': [4000, 1000],
        'max': [10000]
    }
});