生成n个随机数，要求n个数的和等于100

// 生成n个随机数，要求n个数的和等于100
function lessANumber(n, v) {
    var i,
        s = 0,
        r = [],
        x = v;
    for (i = 1; i < n; i++) {
        x = Math.random() * x;
        r.push(x.toFixed(0));
        s += x;
        x = v - s;
    }
    r.push(x.toFixed(0));
    return r;
}

function random(Min,Max){
         var Range = Max - Min;
         var Rand = Math.random();
         return(Min + Math.round(Rand * Range));
    }

    function randnum(n,max){

        var arr = [];
        if(max > 0){
            for(var i = 0;i<n;i++){
                var num = 0;
                    if(i == (n-1)){
                        num = max;
                    }else{
                        if(max <= 0){
                            num = max = 0;
                        }else{
                            num = random(0,max);
                            max -= num;
                        }
                    }
                arr.push(num);
            }
        }
        return arr;
    }

function foo($n ,$max = 100){
    $array = $zero = $normal = [];
    for($i=1;$i<=$n;$i++){
        $array[] = mt_rand(0,100);
    }
    $k = $max / array_sum($array);  //求出放大系数k
    foreach($array as $key => $val){
        $value = floor($val * $k); //直接保留整数，以保证下一步的和肯定<100
        if($value<1){
            $zero[] = $value;
        }else{
            $normal[] = $value;
        }
    }
    $sum = array_sum($normal);
    $diff = $max - $sum; //这个值肯定<100
    if(!empty($zero)){ //如果有为0的值
        $count = count($zero);
        foreach($zero as $z){
            $normal[] = $diff / $count;
        }
    }else{ //随机分配给一个人
        $key = array_rand($normal);
        $normal[$key] = $normal[$key]+$diff;
    }
    unset($array,$zero,$sum,$diff);
    return $normal;
}

javascript里的Math.random() 函数， 在php里

function random($min = 0, $max = 1)
{
    return $min + mt_rand()/mt_getrandmax()*($max-$min);
}