this.evnt.offsetHeight 这句话是什么意思？evnt又是什么属性？

[元明]

//Object constructor

function makeNewsMenu(obj,nest){
nest=(!nest) ? "":'document.'+nest+'.'
this.css=bw.dom? document.getElementById(obj).style:bw.ie4?document.all[obj].style:bw.ns4?eval(nest+"document.layers." +obj):0;
this.evnt=bw.dom? document.getElementById(obj):bw.ie4?document.all[obj]:bw.ns4?eval(nest+"document.layers." +obj):0;
this.scrollHeight=bw.ns4?this.css.document.height:this.evnt.offsetHeight
this.moveIt=b_moveIt;
this.bgChange=b_bgChange;
this.slideUp=b_slideUp;
this.slideDown=b_slideDown;
this.clipTo=b_clipTo;
this.obj = obj + "Object";
eval(this.obj + "=this")
}

[元明]

再声明一下，这段代码是用在<div>标签里的。

[元明]

document.getElementById(obj)
这句话的意思是返回了一个对象吗？

[flylyke]

Returns a reference to the first object with the specified value of the ID attribute.

Syntax

oElement = document.getElementById(sIDValue)
Parameters

sIDValue Required. String that specifies the value of an ID attribute.

Return Value

Returns the first object with the same ID attribute as the specified value.

Remarks

If the ID value belongs to a collection, the getElementById method returns the first object in the collection.

Example

This example uses the getElementById method to return the first occurrence of the ID attribute value, oDiv.

<SCRIPT>
function fnGetId(){
// Returns the first DIV element in the collection.
<!-- @ED mapovey 4/11/2000 :Is this comment in the correct format? -->
var oVDiv=document.getElementById("oDiv");
}
</SCRIPT>
<DIV ID="oDiv">Div #1</DIV>
<DIV ID="oDiv">Div #2</DIV>
<DIV ID="oDiv">Div #3</DIV>
<INPUT TYPE="button" VALUE="Get Names" onclick="fnGetId()">

[flylyke]

看看吧这是document.getElementById的用法

[Keng]

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