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A, Math Basic concepts
- Math and various other objects, it is not a constructor
- It belongs to the tools necessary to create an object,
- Math package inside the properties and methods
- Similar to C # static class
for example
<script type="text/javascript">
//abs();绝对值
console.log(Math.abs(-1));//输出1
</script>
Use Math object
Math. Method name
Two, Math objects common method
2.1 rounding
- Math.ceil (); rounded up into decimal bit value is 1
- Math.floor (); rounding down, give it decimal places
- Math.round (); rounded to whole
operating
<script type="text/javascript">
console.log(Math.ceil(0.12));//输出1
console.log(Math.floor(0.12));//输出0
console.log(Math.round(0.12));//输出0
</script>
2.2 Random Number
- Math.random (); generating a random number (excluding 01) between 0-1
For example
console.log(Math.random());//输出0.3419745734009261
Generating a random number of xy
- Math.round(Math.Random()*(y-x)+x);
Examples 10 to generate random numbers 1-10
<script type="text/javascipt">
for(var i=0;i<10;i++)
{
console.log(Math.round(Math.Random()*9+1));
}
</script>
