js产生随机数

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  • Post category:其他


<script>

document.write(parseInt(10*Math.random()));  //输出0~10之间的随机整数

document.write(Math.floor(Math.random()*10+1));  //输出1~10之间的随机整数

function RndNum(n){

var rnd=””;

for(var i=0;i<n;i++)

rnd+=Math.floor(Math.random()*10);

return rnd;

}

document.write(RndNum(4));  //输出指定位数的随机数的随机整数

引用部分:

. 从1开始 至 任意值

parseInt(Math.random()*上限+1);

. 从任意值开始 至 任意值

parseInt(Math.random()*(上限-下限+1)+下限);

function fRandomBy(under, over){

switch(arguments.length){

case 1: return parseInt(Math.random()*under+1);

case 2: return parseInt(Math.random()*(over-under+1) + under);

default: return 0;

}

}

document.write(fRandomBy(1,100));  //输出指定范围内的随机数的随机整数

</script>

//给既定文本框按规则付不同的值[引申]

<script>

window.οnlοad=function(){

var o=document.getElementsByTagName(‘input’);

o[0].value=fRandomBy(1,10);

o[1].value=fRandomBy(11,20);

o[2].value=fRandomBy(1,100);

o[3].value=fRandomBy(51,100);

}

</script>

-10: <input type=”text” /><br />

-20: <input type=”text” /><br />

-100: <input type=”text” /><br />

-100: <input type=”text” /><br />

<html>

<head>

<title>Math</title>

</head>

<body>

<script language=”javascript” type=”text/javascript”>

total = 0

for(i=1;i<=5000;i++)

{num=Math.random();

total +=num

}

average = total/5000

average = Math.round(average*1000)/1000

document.write(“<h1>平均数:”+average+”</h1>”)

</script>

</body>

</html><script>

document.write(parseInt(10*Math.random()));  //输出0~10之间的随机整数

document.write(Math.floor(Math.random()*10+1));  //输出1~10之间的随机整数

function RndNum(n){


var rnd=””;

for(var i=0;i<n;i++)

rnd+=Math.floor(Math.random()*10);

return rnd;

}

document.write(RndNum(4));  //输出指定位数的随机数的随机整数


引用部分:

. 从1开始 至 任意值

parseInt(Math.random()*上限+1);

. 从任意值开始 至 任意值

parseInt(Math.random()*(上限-下限+1)+下限);

function fRandomBy(under, over){

switch(arguments.length){

case 1: return parseInt(Math.random()*under+1);

case 2: return parseInt(Math.random()*(over-under+1) + under);

default: return 0;

}

}

document.write(fRandomBy(1,100));  //输出指定范围内的随机数的随机整数

</script>

//给既定文本框按规则付不同的值[引申]

<script>

window.οnlοad=function(){

var o=document.getElementsByTagName(‘input’);

o[0].value=fRandomBy(1,10);

o[1].value=fRandomBy(11,20);

o[2].value=fRandomBy(1,100);

o[3].value=fRandomBy(51,100);

}

</script>

-10: <input type=”text” /><br />

-20: <input type=”text” /><br />

-100: <input type=”text” /><br />

-100: <input type=”text” /><br />

<html>

<head>

<title>Math</title>

</head>

<body>

<script language=”javascript” type=”text/javascript”>

total = 0

for(i=1;i<=5000;i++)

{num=Math.random();

total +=num

}

average = total/5000

average = Math.round(average*1000)/1000

document.write(“<h1>平均数:”+average+”</h1>”)

</script>

</body>

</html>