什么是相当于PHP“。=”在Javascript，添加一些变量..？

Question

In PHP you can do:

$myvar = "Hello";
$myvar .= " world!";
echo $myvar;

The output is: Hello world!

How can I do this in Javascript/jQuery..?

Answer 1

var a = 'Hello';
    a += ' world';
alert(a);

You'll get a dialog with "Hello world".

Be careful with this, though:

var a = 3;
    a += 'foo';

Result: 3foo. But:

var a = 3;
    a += 4;
    a += 'b';

You'll get an interesting result, and probably not the one you expect.