如何使用纯JavaScript用img标签替换HTML字符串

Question

We have some content coming from the backend api into an Ionic 2 App. Questions and Answers. Answers have been created using summernote and hence we're able to render raw HTML into the app. But to allow zooming of images, we need to replace all the occurrences of img tag in the answer content.

<img src="pathofimg" attribute1="att1" ...>

With

<ion-scroll scrollX="true" scrollY="true">
  <img src="pathofimg" attribute1="att1" ...>
</ion-scroll>

Using only pure javascript .

I know regex is the good approach but open for suggestions.

Answer 1

As an example, this wraps each child element <span> into a wrapper element <p> . Simply replace the element names and selectors with your own. You may want to use document.querySelector() if your parent element isn't easy to select.

<div>
  <span>0</span>
  <span>1</span>
  <span>2</span>
  <span>3</span>
  <span>4</span>
</div>

<script>
    var commonParentElement = document.getElementsByTagName('div')[0];
    var imgs = commonParentElement.getElementsByTagName('span');

    for (var i=0; i<imgs.length; i++) {
      var wrap = document.createElement('p');
      wrap.setAttribute('style', 'font-weight:bold;');
      wrap.appendChild(imgs[i]);
      commonParentElement.insertBefore(wrap, imgs[i]);
    }
</script>

Here in a plunker

Answer 2

As you added only javascript tag to your question, here is solution using "native" document.getElementsByTagName and element.replaceChild methods:

var images = document.getElementsByTagName('img'),
    len = images.length, img, ion, parent;

while (len--) {
    ion = document.createElement("ion-scroll");
    ion.setAttribute("scrollX", "true");
    ion.setAttribute("scrollY", "true");

    img = images[len];
    parent = img.parentNode;
    ion.innerHTML = img.outerHTML;
    parent.replaceChild(ion, img);
}