javascript - 如何将字符串附加到 Javascript 变量

Question

我有一个 Javascript 变量var test="hello"，我想在函数中将前缀“world”添加到变量的字符串中，以便 test="worldhello"。如何在 JavaScript 代码中编写该命令？

Answer 1

字符串连接： test = "world"+test

Answer 2

var test = "hello";
var newStr = "world" + test;

Answer 3

var test = "hello";
test = test + " world";

或者

var world = " world";
var test = "hello" + world;

Answer 4

var var2 = "world";
test = "hello "+var2;

在一个函数中

function concatenate(str,con){ 
        return str.toString()+con.toString(); //toString() for prevent an int or float sum
 }
var x = concatenate('hello ','world'); //hello world
var y = concatenate(x,"!!!"); //hello world!!!