Element.hasAttribute()
  The Element.hasAttribute() method returns a
  Boolean value indicating whether the specified element has the
  specified attribute or not.
Syntax
var result = element.hasAttribute(name);
result- 
    
holds the return value
trueorfalse. name- 
    
is a string representing the name of the attribute.
 
Example
var foo = document.getElementById("foo");
if (foo.hasAttribute("bar")) {
    // do something
}
Polyfill
;(function(prototype) {
    prototype.hasAttribute = prototype.hasAttribute || function(name) {
        return !!(this.attributes[name] &&
                  this.attributes[name].specified);
    }
})(Element.prototype);
Notes
DOM methods dealing with element's attributes:
| Not namespace-aware, most commonly used methods | Namespace-aware variants (DOM Level 2) | DOM Level 1 methods for dealing with Attr nodes directly (seldom used) | 
DOM Level 2 namespace-aware methods for dealing with Attr nodes directly (seldom used) | 
|---|---|---|---|
setAttribute (DOM 1) | 
setAttributeNS | 
setAttributeNode | 
setAttributeNodeNS | 
getAttribute (DOM 1) | 
getAttributeNS | 
getAttributeNode | 
getAttributeNodeNS | 
hasAttribute (DOM 2) | 
hasAttributeNS | 
- | - | 
removeAttribute (DOM 1) | 
removeAttributeNS | 
removeAttributeNode | 
- | 
Specifications
| Specification | 
|---|
| DOM Standard  # ref-for-dom-element-hasattribute①  | 
Browser compatibility
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