let det = function(x1, x2, y1, y2)  // 行列式
{
    return (x1*y2-x2*y1);
}

let intersect = function(p1, p2, p3, p4)
{
    const delta = det(p2[0]-p1[0], p3[0]-p4[0], p2[1]-p1[1], p3[1]-p4[1]);
    if ( Math.abs(delta) <= 1e-6 ) return false;

    const lambda = det(p3[0]-p1[0], p3[0]-p4[0], p3[1]-p1[1], p3[1]-p4[1]) / delta;
    if ( lambda > 1 || lambda < 0 ) return false;

    const miu = det(p2[0]-p1[0], p3[0]-p1[0], p2[1]-p1[1], p3[1]-p1[1]) / delta;
    if ( miu > 1 || miu < 0 ) return false;

    return true;
}

l1 = [[119.30563100232928, 28.642176833046154], [119.24418299767075,28.642176833046154]]
l2 = [[119.30563100232928, 28.53574576695385], [119.33635500465851,28.5889613]]

let b = intersect(l1[0], l1[1], l2[0], l2[1]);

console.log(b);