Summary of several usages of JavaScript to generate random numbers

<script>   
function GetRandomNum(Min,Max)
{   
var Range = Max - Min;   
var Rand = Math.random();   
return(Min + Math.round(Rand * Range));   
}   
var num = GetRandomNum(1,10);   
alert(num);   
</script>
var chars = [&#39;0&#39;,&#39;1&#39;,&#39;2&#39;,&#39;3&#39;,&#39;4&#39;,&#39;5&#39;,&#39;6&#39;,&#39;7&#39;,&#39;8&#39;,&#39;9&#39;,&#39;A&#39;,&#39;B&#39;,
&#39;C&#39;,&#39;D&#39;,&#39;E&#39;,&#39;F&#39;,&#39;G&#39;,&#39;H&#39;,&#39;I&#39;,&#39;J&#39;,&#39;K&#39;,&#39;L&#39;,&#39;M&#39;,&#39;N&#39;,&#39;O&#39;,&#39;P&#39;,&#39;Q&#39;,&#39;R&#39;,
&#39;S&#39;,&#39;T&#39;,&#39;U&#39;,&#39;V&#39;,&#39;W&#39;,&#39;X&#39;,&#39;Y&#39;,&#39;Z&#39;];
function generateMixed(n) {
     var res = "";
     for(var i = 0; i < n ; i ++) {
         var id = Math.ceil(Math.random()*35);
         res += chars[id];
     }
     return res;
}

Math.random() The result is a random number between 0-1 (including 0, excluding 1)

Math.floor(num) The parameter num is a numerical value, and the function result is the integer part of num.

Math.round(num) The parameter num is a numerical value, and the function result is the integer after num is rounded.

Math: Mathematical object, providing mathematical calculations on data.
Math.random(); Returns a random number between 0 and 1 (including 0, excluding 1).

Math.ceil(n); Returns the smallest integer greater than or equal to n.
When using Math.ceil(Math.random()*10);, we mainly get random integers from 1 to 10, and the probability of getting 0 is very small.

Math.round(n); Returns the value of n after rounding.
Use Math.round(Math.random()); to obtain a random integer from 0 to 1 evenly.
When using Math.round(Math.random()*10);, random integers from 0 to 10 can be obtained in a basically balanced manner, and the probability of obtaining the minimum value 0 and the maximum value 10 is less than half.

Math.floor(n); Returns the largest integer less than or equal to n.
When using Math.floor(Math.random()*10);, random integers from 0 to 9 can be obtained evenly.

Recommended tutorial: "JS Tutorial"

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