CSS Textarea that expands as you type text [duplicate]

Answer 1

function autoExpand(field) {

    // Reset field height
    field.style.height = 'inherit';

    // Get the computed styles for the element
    var computed = window.getComputedStyle(field);

    // Calculate the height
    var height = parseInt(computed.getPropertyValue('border-top-width'), 10)
                 + parseInt(computed.getPropertyValue('padding-top'), 10)
                 + field.scrollHeight
                 + parseInt(computed.getPropertyValue('padding-bottom'), 10)
                 + parseInt(computed.getPropertyValue('border-bottom-width'), 10);

    field.style.height = height + 'px';

};

Works for me

https://gomakethings.com/automatically-expand-a-textarea-as-the-user-types-using-vanilla-javascript/