SOURCE

var a = '1.6';
    console.log(a,typeof(a));
    //第一种
    //a=a-1+1;
    //第二种
    //
    //a=a<<1>>1;
    //a=~~a;
    //第三种
    //a=a*1;
    //第四种
    //a=a/1;
    //5
    a=a|0;
    console.log(a,typeof(a));