btn1 = $('#btn1')
btn1.click(() => location.href = 'page1.html')

btn2 = $('#btn2')
btn2.click(() => location.href = 'page2.html')

btn3 = $('#btn3')
btn3.click(() => location.href = 'page3.html')

imt = () => {
    bb = $('#berat').val()
    tb = $('#tinggi').val()
    imt = bb * 10000 / tb ** 2
    imt = imt.toFixed(1)
    hasil = $('#hasil')
    text1 = ket1(imt)
    // dan seterusnya
}