Methods of referencing objects in javascript_Basic knowledge

51js

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Quotation method within the same page:

1. Use id:

link1.href

2. Use name:

document.all.link1.href

3. Use sourceIndex:

document.all (4).href //Note that there are HTML, HEAD, TITLE and BODY in front, so it is 4

4. Use link collection:

document.anchors(0).href / /All collections include all, anchors, applets, areas, attributes, behaviorsUrns, bookmarks, boundElements, cells, childNodes, children, controlRange, elements, embeds, filters, forms, frames, images, imports, links, mimeTypes, options, plugins , rows, rules, scripts, styleSheets, tBodies, TextRectangle, please refer to MSDN introduction. In fact, Method 3 and Method 4 use the same set, except that one is all, which can include all tags on the page, while anchors only include links.

5. getElementById:

document.getElementById("link1").href

6. getElementsByName:

document.getElementsByName("link1") [0].href //This is also a collection, a collection of all tags whose name is equal to the parameters of this method

7. getElementsByTagName:

document.getElementsByTagName("A")[ 0].href //This is also a set, which is a set of all tags whose tag names are equal to the parameters of the method

8. tags set:

document.all.tags("A ")[0].href //Same as method 7, obtain a collection by tag name

In addition, event.scrElement can get a reference to the tag at the trigger time; document.elementFromPoint(x,y ) can get a reference to the element at the x and y coordinates; document.body.componentFromPoint(event.clientX, event.clientY) can get a reference to the element where the mouse is; it can also be referenced through the parent-child node and sibling node relationships of the element, For example, nextSibling (the node after the current node), previousSibling (the node before the current node), childNodes, children, firstChild, lastChild, parentElement, etc. are all references to parent-child nodes and sibling nodes; it is not limited to this.

The above are common reference methods within the same page, and also involve

============= in different pages
For framing For pages, you can use parent.frames("frame name") and top.frames("frame name") to reference different frames. The subsequent references are the same as those on the same page. Multiple parents are also supported.
For example:
parent.frames("frame1").document.all.link1
top.frames("frame1").document.all.link1

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For the window opened by window.open(), you can use var newwin=window.open(), and then use newwin to reference the new window. The subsequent references are the same as those in the same page. ;The new window can use window.opener to refer to the window that opened it, which can be abbreviated as opener, for example:
var newwin=window.open()
Parent window (here is the window using the window.open() method ):
newwin.document.all.link1 //The parent window sentence can refer to the object in the new window
Child window (the window opened by the window.open() method):
opener.document.all .link1 //The child window can refer to the object of the parent window

Multiple openers are also supported, for example: opener.opener.document.all.link1


There are many methods , sometimes it needs to be determined according to the specific situation and can be used flexibly.