# window.prompt positioning help with prime function

• 11-25-2012, 07:25 PM
k1ngok1ngs
window.prompt positioning help with prime function
Hey i was asked to write two programs. one that determines if an integer is a prime and another to state all the primes between two integers. I have written the first and it works perfectly fine (if not a little over complicated) but I'm having trouble with the second.
I worked out the basic algorithm for it but i cant for the life of me work out how to incorporate two window.promt() into the code without messing it up. there meant for a low and high number for the user to input before receiving all the primes in between those numbers. Here is the basic code.

<html>
<body>
<script language="javascript">

l=1000;n=3;p=1;
primes = new Array()
primes[0]=2;
while (n<=l){q=1;
while (primes[q]<=Math.floor(Math.sqrt(n)) && n/primes[q]!=Math.round(n/primes[q])){q++;}
if ((n-1)/1000==Math.round((n-1)/1000)){window.status="Numbers checked so far: "+(n-1);}
if (n/primes[q]!=Math.round(n/primes[q])){primes[p]=n;p++;}
n+=2;}
document.write ("What follows next are prime numbers:<br>"+primes.join(", "));
</script>
</body>
</html>

I apologise for how messy it is. help would be appreciated I wont have any hair left to pull out soon
• 11-26-2012, 05:01 AM
ZABI
why don't you use forms instead of window.prompt ?
• 11-26-2012, 12:47 PM
007Julien
Do not use document.write ! You will be obliged to reload the page to rerun the script.
Build your page with the following scheme
Code:

```<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN" "http://www.w3.org/TR/html4/strict.dtd"> <html> <head> <meta http-equiv="content-type" content="text/html; charset=utf-8"> <meta name="generator" content="PSPad editor, www.pspad.com"> <title>Prime numbers</title> <style type="text/css"> input{width:40px;text-align:center} </style> </head> <body> <h1>Prime numbers</h1> <!-- a container for the first response --> <div id="rsp"></div> <!-- three inputs for entries and a button--> <p>Displaying the primes between to intergers</p> <label>Min value <input id="mnv" type="text" value=""></label> <label>Max value <input id="mxv" type="text" value=""></label> <input type="button" value="Ok" onclick="calcPrim()"> <!-- a new container for the second response --> <div id="rsq"></div> <!-- The script at the end of the body with a type instead of a language --> <script type="text/javascript"> // Your script l=1000;n=3;p=1; primes = new Array() primes[0]=2; while (n<=l){q=1; while (primes[q]<=Math.floor(Math.sqrt(n)) && n/primes[q]!=Math.round(n/primes[q])){q++;} if ((n-1)/1000==Math.round((n-1)/1000)){document.getElementById('rsp').innerHTML=<p>"Numbers checked so far: "+(n-1)+"</p>";} if (n/primes[q]!=Math.round(n/primes[q])){primes[p]=n;p++;} n+=2;} document.getElementById('rsp').innerHTML="What follows next are prime numbers:<br>"+primes.join(", "); // A function to read the values and to display the result function calcPrim(){         // the + sign convert the values to numbers         var min=+document.getElementById('mnv').value;         var max=+document.getElementById('mxv').value;         // A first test to improve (see isNaN)         if (!min || !max) {alert("Please fill the min and max values !");return}                 // the calculation         // Dislaying the results         document.getElementById('rsq').innerHTML="<p><i>I have only to write the script to list the primes between "+min+" and "+max+".</i></p>"; } </script> </script> </body> </html>```

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