Why alert AnchorElement (<a>) alerts the href attribute?

问题

<a href="url">A link</a>

$.each($('a'), function(index,value){
    alert (value)
});

It will alert : url. Why this happens?

回答1:

It's because the toString() of the anchor gives the URL.

Live DEMO

alert calls toString() implicity on objects. so when you alert an array like:

[1,2,3,4,5,6]

Alerting it will give you:

"1,2,3,4,5,6"

Because the toString() of array is the elements separated by a comma.

If you encounter this problem while debugging, you should use console.log() instead of alert()

回答2:

value is HTMLAnchorElement object, HTMLAnchorElement.toString() method return its url attribute.

alert will use .toString() when display an object.

回答3:

the reason you get url is because .each takes a container(array||object) and then uses your callback function to process the container. it will take an array's elements, or an object's properties, and iterate over them. since the property of your selector object is "href", you will get the url value.

来源：https://stackoverflow.com/questions/11076627/why-alert-anchorelement-a-alerts-the-href-attribute