JS generates random number (specified range) of instance code _javascript tips

1, randomly generated 4-digit random number

<script language= "JavaScript" >
/**
* Randomly generated 4-bit random number
* Http://www.yulu.jb51.net
document.write (parseint (10*math.random ())); 　A random integer document.write between output 0~10 (
Math.floor (Math.random () *10+1)); Output 1~10 The random integer
function rndnum (n) {
 var rnd= "";
 for (Var i=0;i<n;i++)
   Rnd+=math.floor (Math.random () *10);
 return rnd;
}
document.write (Rndnum (4)); Random integer that outputs the random number of a specified number of digits
</script>

2. Randomly generate random number of specified data range

1), starting from 1 to any value

parseint (Math.random () * Upper limit + 1);

2), starting from any value to any value

<script>
parseint (Math.random () * (upper-bound + 1) + lower bound); 
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)); Output random integer </script>//For random number in specified range

give the established text box a different value according to the rules [extended]
<script>
window.onload= 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>
1-10: <input type= "text"/><br/> 11-20 
: <input type= "text"/><br/> 
1-100: <input type= "text"/><br/> 51-100 
: <input type= "text"/><br/>

3, Extended examples:

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