Question

我用JavaScript编写了一个脚本来检查点击的链接是否有效该脚本基本上执行以下操作

拦截所有链接点击
检查它们是否嵌套在body标记
检查网址中是否有某个文字，否则请允许链接
检查该网址是否有效

如果网址为404或其他内容，我希望阻止点击

a[href]

现在它无法正常工作，我感觉function iClicked(event) { var link = event.target; //go up the family tree until A tag while (link && link.tagName != 'A') { link = link.parentNode; } if (link) { var url = link.href; var ajaxurl = link.getAttribute('href'); var needToCheck = url.indexOf('speed') != -1; //check if the url has the string 'speed' in it if (needToCheck) { var reader = new XMLHttpRequest(); //asynchronous is true reader.open('get', ajaxurl, true); //check each time the ready state changes //to see if the object is ready reader.onreadystatechange = checkReadyState; function checkReadyState() { if (reader.readyState === 4) { //check to see whether request for the file failed or succeeded if ((reader.status == 200) || (reader.status === 0)) { //page exists - redirect to the clicked url document.location.href = url; } else { //if the url does not exist alert("No use going there!"); return false; } } } } } return true; } //intercept link clicks document.onclick = iClicked;初始化和ajaxurl与reader.open以及ajaxurl部分有问题。但我还是不能清楚地看到整件事。我对JavaScript很陌生，所以你们可以帮助我吗？

编辑/结束问题感谢@Louy和@epascarello，代码已经完成。

return false

Answer 1

因为@epascarello说你不能在异步回调中使用return。您需要稍后打开链接。

此外，请记住，您无法在新标签中打开链接。 You'll have to open it in a new window or the same window. There's just no way around that.

如果您仍想这样做，请按以下方式进行：

if (!link) return true;

var url = link.href;
var ajaxurl = link.getAttribute('href');
var needToCheck = url.indexOf('speed') != -1;
//check if the url has the string 'speed' in it
if (!needToCheck) return true;

var reader = new XMLHttpRequest();
//asynchronous is true
reader.open('get', ajaxurl, true);
//check each time the ready state changes
//to see if the object is ready
reader.onreadystatechange = checkReadyState;

function checkReadyState() {
  if (reader.readyState === 4) {
    //check to see whether request for the file failed or succeeded
    if ((reader.status == 200) || (reader.status === 0)) {
      //page exists - redirect to the clicked url
      document.location.href = url;
      // or 
      // window.open(url)
    } else {
      //if the url does not exist
      alert("No use going there!");
    }
  }
}

return false;

用于检查网址是否存在的Javascript

1 个答案: