js判断某变量是不是字符串

var str = 'asdf';‍ var str1 = new String('asdf'); typeof str;//"string" typeof str1;//"object" Object.prototype.toString.cal(str); //"[object String]" Object.prototype.toString.call(str1); //"[object String]" 综上所述，判断是否为字符串使用下边的最保险 Object.prototype.toString.call(str) === "[object String]"