如何將一個字符串附加到一個Javascript變量

Question

我有一個Javascript變量var test="hello"我想添加前綴「world」到函數內的變量的字符串，以便test =「worldhello」。如何在JavaScript代碼中編寫該命令？

Answer 1

字符串連接： test = "world"+test

Answer 2

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

Answer 3

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

或

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

Answer 4

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

在函數

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!!!