myNumber.toPrecision( precision ) in ECMAScript 262

By default, the specs require precision to be between 1 and 21 (inclusive). If it is outside this range, an error will be generated. However, specific implementations may extend this range further.

If precision is omitted, toString() is called instead.

var precision = [1,2,3,4];
var numbers = [ 0 , 1.5 , 873 , 10230];
var msg="";
for (var i=0,len=numbers.length;i<en;i++){
    var n = numbers[i];
    for (var j=0,len2=precision.length;j<len2;j++){
        var digits = precision[j];
        msg += "("+n+").toPrecision("+digits+") is '"+n.toPrecision(digits)+"'\n";
    }
}
/**************************
msg is
(0).toPrecision(1) is '0'
(0).toPrecision(2) is '0.0'
(0).toPrecision(3) is '0.00'
(0).toPrecision(4) is '0.000'
(1.5).toPrecision(1) is '2'
(1.5).toPrecision(2) is '1.5'
(1.5).toPrecision(3) is '1.50'
(1.5).toPrecision(4) is '1.500'
(873).toPrecision(1) is '9e+2'
(873).toPrecision(2) is '8.7e+2'
(873).toPrecision(3) is '873'
(873).toPrecision(4) is '873.0'
(10230).toPrecision(1) is '1e+4'
(10230).toPrecision(2) is '1.0e+4'
(10230).toPrecision(3) is '1.02e+4'
(10230).toPrecision(4) is '1.023e+4'
**************************/