我只是想找到输入的数字范围内的素数。我不知道如何计算寻找素数。我需要将它们添加到一个数组中，然后输出该数组。我为计算放置了一个占位符...我似乎不知道如何找到素数。
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN"
"http://www.w3.org/TR/html4/loose.dtd">
<html>
<head>
<meta http-equiv="content-type" content="text/html; charset=utf-8" />
<title>LeapYears</title>
<script type="text/javascript">
/* <![CDATA[ */
function calcPrimeNumber(){
var beginNum = document.numbers.firstNum.value;
var endNum = document.numbers.secondNum.value;
var primeNumbs = new Array();
var ctr = 0;
while (beginNum <= endNum){ //throwaway
if ((beginNum % beginNum == 0) && (beginNum % 1 == 0)){
primeNumbs[ctr] = beginNum;
++ctr;
}
++beginNum;
}
if (primeNumbs == 0){
window.alert("There were no leap years within the range.");
}
else {
outputPrimeNums(primeNumbs);
}
}
function outputPrimeNums(primes){
document.write("<h2>Prime Numbers</h2>");
for (i=0;i<primes.length;i++){
document.write(primes[i] + "<br/>");
}
}
/* ]]> */
</script>
</head>
<body>
<form name="numbers">
Beginning Number: <input type="text" name="firstNum" /> End Number: <input type="text" name="secondNum" />
<input type="button" value="Find Prime Numbers" onclick="calcPrimeNumber()" />
</form>
</body>
</html>
最佳答案
尝试这一整页的 prime no 示例
<html>
<head>
<meta http-equiv="content-type" content="text/html; charset=utf-8" />
<title>LeapYears</title>
<script type="text/javascript">
/* <![CDATA[ */
function calcPrimeNumber(){
var beginNum = parseInt(document.numbers.firstNum.value);
var endNum = parseInt(document.numbers.secondNum.value);
var primeNumbs = new Array();
var ctr = beginNum;
while(ctr<=endNum)
{
if(isPrime(ctr)==true)
{
primeNumbs[primeNumbs.length] = ctr;
}
ctr = ctr+1;
}
if (primeNumbs.length == 0){
document.getElementById('output_content').innerHTML = "There were no prime no within the range.";
}
else {
outputPrimeNums(primeNumbs);
}
}
function isPrime(num)
{
var flag = true;
for(var i=2; i<=Math.ceil(num/2); i++)
{
if((num%i)==0)
{
flag = false;
break;
}
}
return flag;
}
function outputPrimeNums(primes){
var html = "<h2>Prime Numbers</h2>";
for (i=0;i<primes.length;i++){
html += primes[i] + "<br/>";
}
document.getElementById('output_content').innerHTML = html;
}
/* ]]> */
</script>
</head>
<body>
<form name="numbers">
Beginning Number: <input type="text" name="firstNum" /> End Number: <input type="text" name="secondNum" />
<input type="button" value="Find Prime Numbers" onclick="calcPrimeNumber()" />
</form>
<div id="output_content">
</div>
</body>
</html>
关于javascript - 如何在输入的数字范围内查找质数，我们在Stack Overflow上找到一个类似的问题： https://stackoverflow.com/questions/21795543/