Aaclass () Encapsulates a common function, classnames property substitution instead of appending an issue

Function styleheaderssiblings () {if (!document.getelementsbytagname)  return false;var  Headers = document.getelementsbytagname ("H1"); for (var i = 0;i <  headers.length; i++) {var elem = getnextelement (headers[i].nextsibling);//elem.style.color  =  "Red";//elem.style.fontsize =  "1.2em";//The following uses the ClassName property, which is a substitution, not an append//elem.classname  =  "Intro";                   //.intro{ color:red;font-size:1.2em;} AddClass (Elem, "Intro");//Call encapsulation function}}//elem.classname += " intro"      note, The first character of the intro is a space, which means that the new CALSS attribute is appended to the original attribute//If there is no attribute in the original, then the classname is directly assigned, without the need to append//So we can encapsulate the above steps into a function for general function  AddClass (Element,value) {if (!element.classname) {element.classname = value;} else{newclassname = element.classname;newclassname +=  "";newclassname += value; Element.cLassname = newclassname;}} 

Aaclass () encapsulates a common function, classnames property substitution instead of appending an issue