Question

我正在开发一个类似于以下内容的javascript代码。我只是首先展示代码的基本框架。

var array = [];

function mainFun()
{
     A();
}
function A()
{
    //some code
    B();
    //code to print all values in "array"
}

function B()
{
    C();
}

function C()
{
     //some code
     //push elements one by one in "array"
     for (var i=0; i<10; i++)
     {
           array.push(i); //something on these lines
     }
}

我知道这段代码看起来很奇怪，但这正是我正在研究的情况。感谢Javascript的函数级别作用域（与常规块级作用域相比），我无法访问和打印A()中已推送到C()数组中的所有元素。那么如何让我的数组变量像一个真正的全局变量一样工作，该变量知道什么元素被推入它？

好的，这是我的原始源代码（我不知道虚拟代码是如何工作的！）

var allLinks = {}; //set of all internal and external links
var Queued = [];
var crawlingURL;
var Crawled = [];
var xmlHttp = null, originURL, maxHops = 0, currentHop = 0;

function changeText(){
    var tabID, sourceURL;
    chrome.tabs.query({currentWindow: true, active: true}, function(tabs){
        console.log(tabs[0].url);
        document.getElementById('URL').innerHTML="URL of Current Page : "+tabs[0].url;
        tabID = tabs[0].id;
        sourceURL = tabs[0].url;

        Queued.push(sourceURL); //push the origin link the Queued array to begin crawling
        beginCrawl(sourceURL);
    });
}

document.addEventListener('DOMContentLoaded', function () {
    changeText();
});

function beginCrawl(url)
{
    originURL = url;
    maxHops = 2;
    currentHop = 1;
    var queueIndex = 0;
    //httpGet(originURL);
    while(queueIndex<1) //(currentHop <= maxHops)
    {
        crawlingURL = Queued[queueIndex];
        //allPages[crawlingURL] = {url:url, state:"crawling", level:0, host:startingHost};
        httpGet(crawlingURL);
        Crawled.push(crawlingURL);
        queueIndex++;

        for(var j = 0; j < Queued.length; j++)
        {
            console.log(j+". "+Queued[j]+"\n");
        }
    }
}
function httpGet(theUrl)
{
    xmlHttp = new XMLHttpRequest();
    xmlHttp.open( "GET", theUrl, true );
    xmlHttp.send( null );
    xmlHttp.onreadystatechange = ProcessRequest;
}

function ProcessRequest()
{
    if ( xmlHttp.readyState == 4 && xmlHttp.status == 200 ) // xmlHTTP success
    {           
            var container = document.createElement("p");
            container.innerHTML = xmlHttp.responseText;
            var anchors = container.getElementsByTagName("a");
            var list = [];
            for (var i = 0; i < anchors.length; i++) 
            {
                var href = anchors[i].href;
                var exists = 0;

                // to check for duplicate entries in the list
                    for(var j = 0; j < Queued.length; j++)  // remove duplicates
                        if(Queued[j] == href)
                            exists = 1;
                    if (exists == 0)
                    {
                        Queued.push(href);
                        document.getElementById('printORGLinks').innerHTML += href + "<br />";
                    }
            }
        }
}

我无法打印我的排队数组中的值！（您可能已经理解，这是某种网络爬虫的初步代码。我需要获取推入排队数组的所有URL列表。）

Answer 1

这就像你输入它一样 - 在这里摆弄http://jsfiddle.net/LmFqq/1/

输出

some code executing in A()
some code executing in B()
adding elements in C()
printing in A()
[0,1,2,3,4,5,6,7,8,9]

代码

var array = [];
var el = document.getElementById('output');
mainFun();

function log(msg) {
    el.innerHTML += msg + "<br />";
}

function mainFun()
{
     A();
}

function A()
{
    log("some code executing in A()");
    B();

    log("printing in A()");
    log(JSON.stringify(array));
}

function B()
{
    log("some code executing in B()");
    C();
}

function C()
{
    log("adding elements in C()");
     for (var i=0; i<10; i++)
     {
           array.push(i); //something on these lines
     }
}

无法使用javascript将值读入全局数组变量

1 个答案: