您可以使用一元运算符'+'或parseInt(number，10)或Number()将字符串转换为数字

You can convert a string to number using unary operator '+' or parseInt(number,10) or Number()

检查这些代码段

var num1a = "1";
console.log(+num1a);

var num1b = "2";
num1b=+num1b;
console.log(num1b);


var num3 = "3"
console.log(parseInt(num3,10));


var num4 = "4";
console.log(Number(num4));

希望有帮助