Internationalize your WordPress javascripts

js_localization.php

// the php file
<?php
wp_enqueue_script( 'custom-js', get_bloginfo( 'stylesheet_directory' ) . '/js/custom.js', array( 'jquery' ), '1.0' );

wp_localize_script(
	'custom-js',
	'theme_custom_js_i18n',
	array(
		'checkYourMail' => __( 'We\'ve sent you an e-mail with a link. Please click it to confirm your e-mail.' )
	)
);
?>

// then in the js file you have a global variable called theme_custom_js_i18n which contains the array json_encode-ed
<script>
	$(document).ready(function(theme_custom_js_i18n){
		var checkYourMailHtml = theme_custom_js_i18n.checkYourMail;
	});
</script>