network_settings_add_js

network_settings_add_js：这个动作钩子用于为网络设置页面提供脚本。

在网络设置屏幕的标题中打印JavaScript。

function network_settings_add_js() {
	?>
<script type="text/javascript">
jQuery( function($) {
	var languageSelect = $( '#WPLANG' );
	$( 'form' ).on( 'submit', function() {
		// Don't show a spinner for English and installed languages,
		// as there is nothing to download.
		if ( ! languageSelect.find( 'option:selected' ).data( 'installed' ) ) {
			$( '#submit', this ).after( '<span class="spinner language-install-spinner is-active" />' );
		}
	});
} );