求一正则表达式

Question

要求0到1的两位小数（包括1和0）

Answer 1

<script>
var fact =0;
for ( i = 1; i < 100; i++) {
    fact = fact + 0.01;
    document.write(i + "! = " + fact + "<br>");
}
</script>

Answer 2

var patrn=/^[0-9]{1,20}$/; 
//判断是否是数字
if (!patrn.exec(s)) {return false }

Answer 3

var reg = /^0(\.\d{1,2})?$|^1(\.00?)?$/;
var arr = ["0","0.0","0.00","1","1.0","1.00","-1","0.2","0.33","0.123","1.01","a","a.b"];
for(var i=0;i<arr.length;i++)
 alert(arr[i]+"--"+reg.test(arr[i]));

Answer 4

结果：
</code>
0--true
0.0--true
0.00--true
1--true
1.0--true
1.00--true
-1--false
0.2--true
0.33--true
0.123--false
1.01--false
a--false
a.b--false
</pre>

Answer 5

var arr = ["0","0.0","0.00","1","1.0","1.00","-1","0.2","0.33","0.123","0.30","1.01","a","a.b"];
var re = /^0(\.(?=\d?[1-9]$)\d{1,2})?$|^1$/;
for(var i = 0, len = arr.length; i < len; i++){
re.test(arr[i])?
document.write( arr[i] +' ---- <span style="color:red">'+re.test(arr[i])+'</span><br/>' )
:
document.write( arr[i] +' ---- '+re.test(arr[i])+'<br/>' );
}