1、字符转换
s1 = -s1; //value becomes numeric -1
s2 = -s2; //value becomes numeric -1.1
s3 = -s3; //value becomes NaN
b = -b; //value becomes numeric 0
f = -f; //change to -1.1
o = -o; // 1 先执行对象的valueOf()方法返回-1,--1为1
o = +o;//-1 o的valueOf()值为-1，+-1还是-1
s2 = -s2; //value becomes numeric -1.1
s3 = -s3; //value becomes NaN
b = -b; //value becomes numeric 0
f = -f; //change to -1.1
o = -o; // 1 先执行对象的valueOf()方法返回-1,--1为1
o = +o;//-1 o的valueOf()值为-1，+-1还是-1
2、特殊字符运算
3、变量转字符串运算
alert(String(value1)); //"10"
alert(String(value2)); //"true"
alert(String(value3)); //"null"
alert(String(value4)); //"undefined"
alert(String(value2)); //"true"
alert(String(value3)); //"null"
alert(String(value4)); //"undefined"
4、数字的进制转换
5、字符串比较运算
3; //true
var result2 = 5 < 3; //false
var result3 = "Brick" < "alphabet"; //true 字符串比较按照字母表顺序进行比较 小写字母在大写字母后面
var result4 = "Brick".toLowerCase() < "alphabet".toLowerCase(); //false字母表顺序比较
var result5 = "23" < "3"; //true 字符2小于字符3
var result6 = "23" < 3; //false 此时'23'转换成23了
var result7 = "a" < 3; //false because "a" becomes NaN 字符'a'无法转换成数字
var result8 = NaN < 3; //false NaN 和任何数字比较，都无法转换成数字，所以一直是false
var result9 = NaN >= 3; //false
6、字符进制转换
输出十进制数据 10*16+15*1
var num2 = parseInt("AF"); //NaN 没有指定进制，默认按照10进制转换，由于AF不在十进制范围，返回NaN
alert(num1);
alert(num2);