javascript getElementById usage and usage_javascript skills

document.getElementById("link").href;
document.getElementById("link").target;
document.getElementById("img").src;
document.getElementById("img") .width;
document.getElementById("img").height;
document.getElementById("input").value;
So how to get

and ? For example, aaa in

aaa

, and bbb in bbb are also very simple, using innerHTML That's it:
document.getElementById("div").innerHTML;
document.getElementById("link").innerHTML;
getElementById method
returns the first one with the specified ID attribute value A reference to the object.
Syntax
oElement = document.getElementById(sIDValue)
Parameters
sIDValue is required. A string indicating the value of the ID attribute
Return value
Returns the first object whose ID attribute value is the same as the specified value.
Notes
If the ID belongs to a collection, the getElementById method returns the first object in the collection.
The getElementById method is equivalent to using the item method on the all collection. For example, the following code sample shows how to retrieve the first feature with ID oDiv from a document object.
Use DHTML Object Model:
var oVDiv = document.body.all.item("oDiv");
Use Document Object Model (DOM):
var oVDiv = document.getElementById("oDiv ");
Example
The following example shows how to use the getElementById method to return the first occurrence of the ID attribute value oDiv.
<script> <br>function fnGetId(){ <br>// Returns the first DIV element in the collection. <br>var oVDiv=document.getElementById("oDiv1"); <br>} <br></script>

Div #1

Div #2

< ;DIV ID="oDiv3">Div #3

getElementById method
Returns the first one with the specified ID attribute value. For example, there is a text box in a web page with an id called text1
getElementById(text1) can get the object of this text1 box and use all the properties and methods of the text box
This is a JS method, which means to get the value of an element through the control ID, such as text, label, etc. in a form. They are all elements of FORM and have an assigned ID. getElementById() is to get these elements. of text value.
This is a JS method, which means to obtain the value of an element through the control ID, such as a form containing text, label, etc. They are all elements of FORM and have an assigned ID. getElementById() obtains these The text value of the element.
Program Example

<table width="60%" id="myTable" border="1"> <tr> <td>行1 单元格1</td> <td>行1 单元格2</td> </tr> <tr> <td>行2 单元格1</td> <td>行2 单元格2</td> </tr> <tr> <td>行3 单元格1</td> <td>行3 单元格2</td> </tr> </table> <form> <input type="button" onclick="alignRow()" value="右对齐第一行文字"> </form>
[Ctrl A Select all Note: If you need to introduce external Js, you need to refresh to execute

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Detachments are aligned one unit at a time

<table id="myTable" border="1" width="100%"> <tr> <td>单元格1</td> <td>单元格2</td> </tr> <tr> <td>单元格3</td> <td>单元格4</td> </tr> </table> <form> <input type="button" onclick="alignCell()" value="居中对齐第一个单元格的内容"> </form>
[Ctrl A Select all Note:

If you need to introduce external Js, you need to refresh to execute
]

Change the value of colspan <table id="myTable" border="1"> <tr> <td colspan="4">单元格1</td> <td colspan="4">单元格2</td> </tr> <tr> <td>单元格3</td> <td>单元格4</td> <td>单元格5</td> <td>单元格6</td> <td>单元格7</td> <td>单元格8</td> <td>单元格9</td> <td>单元格10</td> </tr> </table> <script type="text/javascript"> function alignRow() { var x=document.getElementById('myTable').rows x[0].align="right" } </script> <script type="text/javascript"> function alignCell() { var x=document.getElementById('myTable').rows[0].cells x[0].align="center" } </script> <script type="text/javascript"> function setColSpan() { var x=document.getElementById('myTable').rows[0].cells x[0].colSpan="2" x[1].colSpan="6" } </script><form> <input type="button" onclick="setColSpan()" value="改变colspan值"> </form>
[Ctrl A select all Note: If you need to introduce external Js, you need to refresh to execute ]