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Question

我正在处理用户脚本，我刚刚发现当主页发出AJAX请求时脚本没有运行。

有没有办法在主页加载和AJAX请求上激活用户脚本？

Answer 1

在AJAX请求上重新运行脚本代码的聪明方法是关注页面的关键位并检查更改。

例如，假设一个页面包含HTML，如下所示：

<div id="userBlather">
    <div class="comment"> Comment 1... </div> 
    <div class="comment"> Comment 2... </div> 
    ... 
</div>

并且您希望脚本在每个注释中执行某些操作。

现在你可以拦截所有AJAX调用，~~或者监听DOMSubtreeModified~~ （已弃用），或者使用MutationObserver s，但这些方法可以变得棘手，挑剔，过于复杂。

在野外页面上获取ajax-ified内容的一种更简单，更健壮的方法是使用类似waitForKeyElements函数的内容进行轮询。

例如，此脚本将突出显示包含＆＃34; beer＆＃34;的注释，因为它们是AJAX-in：

// ==UserScript==
// @name            _Refire on key Ajax changes
// @include         http://YOUR_SITE.com/YOUR_PATH/*
// @require         http://ajax.googleapis.com/ajax/libs/jquery/1.6.2/jquery.min.js
// ==/UserScript==

function highlightGoodComments (jNode) {

    //***** YOUR CODE HERE *****

    if (/beer/i.test (jNode.text () ) ) {
        jNode.css ("background", "yellow");
    }
    //...
}
waitForKeyElements ("#userBlather div.comment", highlightGoodComments);

/*--- waitForKeyElements():  A utility function, for Greasemonkey scripts,
    that detects and handles AJAXed content.

    IMPORTANT: This function requires your script to have loaded jQuery.
*/
function waitForKeyElements (
    selectorTxt,    /* Required: The jQuery selector string that
                        specifies the desired element(s).
                    */
    actionFunction, /* Required: The code to run when elements are
                        found. It is passed a jNode to the matched
                        element.
                    */
    bWaitOnce,      /* Optional: If false, will continue to scan for
                        new elements even after the first match is
                        found.
                    */
    iframeSelector  /* Optional: If set, identifies the iframe to
                        search.
                    */
) {
    var targetNodes, btargetsFound;

    if (typeof iframeSelector == "undefined")
        targetNodes     = $(selectorTxt);
    else
        targetNodes     = $(iframeSelector).contents ()
                                           .find (selectorTxt);

    if (targetNodes  &&  targetNodes.length > 0) {
        btargetsFound   = true;
        /*--- Found target node(s).  Go through each and act if they
            are new.
        */
        targetNodes.each ( function () {
            var jThis        = $(this);
            var alreadyFound = jThis.data ('alreadyFound')  ||  false;

            if (!alreadyFound) {
                //--- Call the payload function.
                var cancelFound     = actionFunction (jThis);
                if (cancelFound)
                    btargetsFound   = false;
                else
                    jThis.data ('alreadyFound', true);
            }
        } );
    }
    else {
        btargetsFound   = false;
    }

    //--- Get the timer-control variable for this selector.
    var controlObj      = waitForKeyElements.controlObj  ||  {};
    var controlKey      = selectorTxt.replace (/[^\w]/g, "_");
    var timeControl     = controlObj [controlKey];

    //--- Now set or clear the timer as appropriate.
    if (btargetsFound  &&  bWaitOnce  &&  timeControl) {
        //--- The only condition where we need to clear the timer.
        clearInterval (timeControl);
        delete controlObj [controlKey]
    }
    else {
        //--- Set a timer, if needed.
        if ( ! timeControl) {
            timeControl = setInterval ( function () {
                    waitForKeyElements (    selectorTxt,
                                            actionFunction,
                                            bWaitOnce,
                                            iframeSelector
                                        );
                },
                300
            );
            controlObj [controlKey] = timeControl;
        }
    }
    waitForKeyElements.controlObj   = controlObj;
}

更新

为方便起见，waitForKeyElements()现在为hosted on GitHub。

This answer shows an example of how to use the hosted function

Answer 2

另一种方式 - 更简单，更小但更不灵活 - 是使用JavaScript时间延迟来等待AJAX / jQuery加载和完成。例如，如果在首次加载后动态生成以下HTML：

<div id="userBlather">
    <div class="comment"> Comment 1... </div> 
    <div class="comment"> Comment 2... </div> 
    ... 
</div>

然后像这样的greasemonkey脚本可以修改它：

// Wait 2 seconds for the jQuery/AJAX to finish and then modify the HTML DOM
window.setTimeout(updateHTML, 2000);

function updateHTML()
{
    var comments = document.getElementsByClassName("comment");
    for (i = 0; i < comments.length; i++)
    {
        comments[i].innerHTML = "Modified comment " + i;
    }
}

请参阅此处的指南：Sleep/Pause/Wait in Javascript

关于AJAX请求的Fire Greasemonkey脚本

2 个答案:

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