php 压缩 js

<?php
function compress_js($js_code) {
    // 删除注释
    $js_code = preg_replace('!//.*!','',$js_code);
    $js_code = preg_replace('!/\*[^*]*\*+([^/][^*]*\*+)*/!','',$js_code);
    // 删除空格和换行
    $js_code = preg_replace('/\s+/', ' ', $js_code);
    return trim($js_code);
}

$js = "function test() {
    // 这是一个测试函数
    var a = 1; 
    var b = 2;
    return a + b;
}";
$compressed_js = compress_js($js);
echo $compressed_js;
?>