Attribute Value in Javascript

Question

I am creating an image tag using the following code..

var a = new DOMParser().parseFromString('<img src="/hello" alt="Promised">', "text/xml");
for(var b in a){
    alert('b is: ' + b + '.Value is: ' + a[b]);
}

In the above code, I am not able to get the value of alt attribute of image. Why is alt not displayed in the for loop?

I know we can get the attribute as:

var a = document.getELementsByTagName('img')[0].alt;

But why is it not working inside of for loop?

Why are you using a loop if your code only returns a single element? — Einar Ólafsson
– Einar Ólafsson, Commented Dec 13, 2018 at 18:08
@EinarÓlafsson He's trying to loop over that element's attributes, not over a collection of elements. — user47589
– user47589, Commented Dec 13, 2018 at 18:10
I am using it to get all the attribute values of img tag..Here b is attribute name and a[b] is attribute value — Akshit Gupta
– Akshit Gupta, Commented Dec 13, 2018 at 18:10

score 1 · Accepted Answer · 2018-12-13 18:14:22Z

1

It doesn't help that you are parsing it as XML, yet it isn't valid XML (no closing tag). Try this:

new XMLSerializer().serializeToString(a)

You get this parser error:

<img src="/hello" alt="Promised">
    <parsererror xmlns="http://www.w3.org/1999/xhtml" style="display: block; white-space: pre; border: 2px solid #c77; padding: 0 1em 0 1em; margin: 1em; background-color: #fdd; color: black">
        <h3>This page contains the following errors:</h3>
        <div style="font-family:monospace;font-size:12px">error on line 1 at column 34: Extra content at the end of the document
        </div>
        <h3>Below is a rendering of the page up to the first error.</h3>
    </parsererror>
</img>

If you fix the XML (closing tag) and repeat, you get:

var a = new DOMParser().parseFromString('<img src="/hello" alt="Promised"></img>', "text/xml");
new XMLSerializer().serializeToString(a)

Results in:

<img src="/hello" alt="Promised"/>

If you parse it as HTML instead:

var a = new DOMParser().parseFromString('<img src="/hello" alt="Promised">', "text/html");

You'll get this instead:

<html xmlns="http://www.w3.org/1999/xhtml">
    <head></head>
    <body>
        <img src="/hello" alt="Promised" />
    </body>
</html>

To loop over the element's attributes, you need to fix your loop:

var elem = a.getElementsByTagName('img')[0];
for (var i = 0; i < elem.attributes.length; i++) {
    var attrib = elem.attributes[i];
    if (attrib.specified) {
        console.log('b is: ' + attrib.name + '.  Value is: ' + attrib.value);
    }
}

edited Dec 13, 2018 at 18:14

answered Dec 13, 2018 at 18:00

user47589

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1 Comment

Akshit Gupta Over a year ago

Thank You for your answer.. How can I get alt value inside of for loop?

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