为所有图像添加 Alt 属性 - Vanilla Javascript

Question

How would I be able to loop through all the images, retrieve the image title, then add it to the alt attribute?

function addAltAtrr() {
    //get the images
    let grabImage = document.querySelectorAll("img"); 
     
    //loop through all images
    for (let i = 0; i < grabImage.length; i++) {  
        grabImage[i].setAttribute("alt", "test");   
    }

}

addAltAtrr();

This currently adds the string "text" as an alt attribute

Answer 1

You can use the alt and title properties, which reflect the attributes of the same names. This is assuming by "title" you mean the title attribute, which shows as a hover tooltip. If you mean the file name, you could use the image element's src , but you'll probably want to process it, removing the file extension for instance.

Also note that screen readers may speak both alt and title , which would be redundant if one is based on the other.

function addAltAttrs() {
    //get the images
    let images = document.querySelectorAll("img"); 
     
    //loop through all images
    for (let i = 0; i < images.length; i++) {
        //add alt text if missing (but title is present)
        if (images[i].title && !images[i].alt) {
            images[i].alt = images[i].title;
        }
    }

}

addAltAttrs();