rational approximation generator.html

<html>
<head>
<title>rational approximation generator</title>
<script>

 function go_(){

 var rf = (inpt.value<1)?1:0;
 var num = (rf)?1/inpt.value:inpt.value;
 var num0 = 0;
 var den0 = 0;
 var num1 = 1;
 var den1 = 0;
 var num2 = Math.floor(num);
 var den2 = 1;
 var str = "";

 function frac_str(){return((rf)?den2:num2) + " / " + ((rf)?num2:den2) + "<br>";}

 str = frac_str();
 for (var i=1; i<no_of.value; i++){
 num0 = num1;  den0 = den1;  num1 = num2;  den1 = den2;
 num = 1 / (num - Math.floor(num));
 num2 = num1 * Math.floor(num) + num0;  den2 = den1 * Math.floor(num) + den0;
 str += frac_str();
 }
 out.innerHTML = str
 }
</script>

</head>

<body>

Javascript to generate rational approximations<br>
There's no attempt to sanitize the input or make sure
the output makes sense.<br>
If you put in garbage you get garbage out.<br>
If you put in a rational number you will likely get some garbage,<br>
sooner rather than later in the case of eg integers.<br>
And since you can only input rational numbers ...<br><br>

<input id="inpt" type="text" size="16" value="3.14159265359" onchange="go_()"><button type="button" onclick="go_()">go</button>&nbsp;&nbsp;

<input type="number" id="no_of" size="4" value = "8" onchange="go_()" min="1" max="99"><br>

<div id="out"></div>

</body>
</html>