javascript - getting function itself among its parameters -

have simple function applying given attributes dom-element:

object.prototype.setattr = function(attr) { // attr object   ( var in attr )      this.setattribute( i, atr[i] ); };

in addition passed parameters i'm getting function setattr itself. can explain behavior?

you need use hasownproperty avoid looping through prototype chain.

since attr object , have added setattr prototype of object, attr has access setattr method through prototype chain.

object.prototype.setattr = function(attr) { // attr object    (var in attr) {      if (attr.hasownproperty(i))        this.setattribute(i, attr[i]);    }  };      item.setattr({    b: 1  });

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