您需要utf8_encode()输出数据。无需在客户端将编码设置为 UTF-8,因为它已经是默认编码。
<?php\n if( isset( $_GET['json'] ) ) {\n\n die( json_encode( array( 'text' => utf8_encode( '\xc3\xb5, \xc3\xbc. \xc3\xa4, \xc3\xb6' ) ) ) );\n }\n\n include_jquery(); # this outputs jquery include\n>?\n\n<script>\n\n $.getJSON( 'this_file.php', { 'json': 1 }, function( data ) {\n console.log( 'data', data );\n });\n\n</script>\nRun Code Online (Sandbox Code Playgroud)\n