javascript - 复杂的javascript代码，我可以删除它吗？或者它有什么作用？

Question

在我的网站 www.theprinterdepo.com 中，您可以查看页面源代码，我有一个代码，我的 seo 咨询建议我将其移至外部文件。

它是一个基于 magento 构建的电子商务网站。它是一个免费的开源工具，所以我没有开发它，我只是安装了它。

我需要知道代码的作用。

window.HDUSeed='c7025284683262a8eb81056c48968d74';
window.HDUSeedIntId = setInterval(function(){
    if (document.observe) {
        document.observe('dom:loaded', function(){
            for (var i = 0; i < document.forms.length; i++) {
                if (document.forms[i].getAttribute('action') &&  document.forms[i].getAttribute('action').match('contacts/index/post')) {
                    var el = document.createElement('input');
                    el.type = ('hidden');
                    el.name = 'hdu_seed';
                    el.value = window.HDUSeed;
                    document.forms[i].appendChild(el);
                }
            }
        });
        clearInterval(window.HDUSeedIntId)
    }
}, 100);

Answer 1

简介

此脚本调用 interval 处的函数每 100 毫秒左右 ( as it's not guaranteed ) 尝试验证 DOM 的加载状态以在其上添加一个钩子(Hook)。

如果加载，它会处理页面中存在的所有表单，寻找具有“action”属性的表单(通常将其提交到某个地方，此处 contacts/index/post )。

对于找到的所有此类表单，它添加了一个包含“种子”值的新隐藏输入元素，但如果不了解更多有关代码库的信息，我们无法告诉您它的用途。

详细代码审查

// seed value, purpose unknown
window.HDUSeed='c7025284683262a8eb81056c48968d74';

// invoke this function every 100ms
//   see: https://developer.mozilla.org/en/DOM/window.setInterval
window.HDUSeedIntId = setInterval(function(){
    // checks if document.observe method exists (added by the Prototype
    // JavaScript library, so we use this here to check its presence or
    // that it's been already loaded)
    if (document.observe) {
        // hook on load status (when the page's DOM has finished loading)
        //   see: http://www.prototypejs.org/api/document/observe
        document.observe('dom:loaded', function(){
            // process all forms contained within the page's context
            //   see: https://developer.mozilla.org/en/DOM/document.forms
            for (var i = 0; i < document.forms.length; i++) {
                // only act on forms with the 'contacts/index/post/' action attribute
                //   see: https://developer.mozilla.org/en/DOM/document.forms
                //   and: https://developer.mozilla.org/en/JavaScript/Reference/Global_Objects/String/match
                if (document.forms[i].getAttribute('action') && 
                    document.forms[i].getAttribute('action').match('contacts/index/post')) {
                    // create an element...
                    //   see: https://developer.mozilla.org/en/DOM/document.createElement
                    var el = document.createElement('input');
                    el.type = ('hidden');              // ... that is hidden
                    el.name = 'hdu_seed';              // w/ name 'hdu_seed'
                    el.value = window.HDUSeed;         // and the seed value
                    document.forms[i].appendChild(el); // and add it to the end of the form
                }
            }
        });
        // Remove the interval to not call this stub again,
        // as you've done what you want.
        // To do this, you call clearInterval with the ID of the
        // interval callback you created earlier.
        //   see: https://developer.mozilla.org/en/DOM/window.clearInterval
        clearInterval(window.HDUSeedIntId)
    }
}, 100); // 100ms