php下载文件，用错了

今需要在页面下载文件，就找了个php的方法

public function _downloads($path){
        $filename = basename($path);
        $dirname  = dirname($path);
        if(!file_exists($path)){
            Header("Content-type: text/html; charset=utf-8");
            echo "file $path does not exist";
            exit();
        }else{
            $file = fopen($path,'r');
            Header("Content-type: application/octet-stream");
            Header("Accept-Ranges: bytes");
            Header("Accept-Length: ".filesize($path));
            Header("Content-Disposition: attachment; filename=".$filename);
            echo fread($file,filesize($path));
            fclose($file);
            exit();
        }
    }

以ajax方式调用，怎么都下载不了，后来明白了，直接用js就行了，这样调用也是错误的

window.location.href = path;

就这样一句js就搞定了，感到自己知识浅薄啊，。。。