Question

我想通过PHP DomDocument解析HTML网页，并从其alt属性中提取img。像getElementById()这样的函数。有办法吗？

Answer 1

DOMDocument有一个名为getElementsByTagName的方法，可用于按标签名称获取元素。例如

// a date before DST starts
var beforeDstUtc = new DateTime(2018, 3, 1, 13, 0, 0, DateTimeKind.Utc);
// a date after DST starts
var afterDstUtc = new DateTime(2018, 4, 1, 13, 0, 0, DateTimeKind.Utc);

var cstZone = TimeZoneInfo.FindSystemTimeZoneById("Central Standard Time");

var cstTime1 = TimeZoneInfo.ConvertTimeFromUtc(beforeDstUtc, cstZone);
var cstTime2 = TimeZoneInfo.ConvertTimeFromUtc(afterDstUtc, cstZone);

var expectedBeforeDstLocal = new DateTime(2018, 3, 1, 07, 0, 0, DateTimeKind.Local);
var expectedAfterDstLocal = new DateTime(2018, 4, 1, 08, 0, 0, DateTimeKind.Local);

// should be -6 hours
Assert.AreEqual(expectedBeforeDstLocal, cstTime1);
// should be -5 hours
Assert.AreEqual(expectedAfterDstLocal, cstTime2);

这会给出

    <?php
    $htmlStr = <<<EOD
    <!DOCTYPE html>
    <html>
    <head>
    <title>Some nice page</title>
    </head>
    <body>

    <h1>Something nice</h1>
    <img id="beautiful-para" src="https://" alt="foo-hj" />

    </body>
    </html>
    EOD;

    $doc = new DomDocument;

    $doc->validateOnParse = true;
    $doc->loadHTML($htmlStr);
   $images = $doc->getElementsByTagName('img');

  foreach ($images as $image) {
      var_dump($image->getAttribute('alt'));
   }

希望这有帮助。

如何让img src形成其alt？

1 个答案: