Three ways to summarize the value of a control in jquery _jquery

A jquery method of obtaining server control values
Since the ASP.net Web page is running, the server control will randomly generate the client Id,jquery acquisition time is not very good operation, Google, the summary has the following 3 ways:

Server control code: <asp:textbox id= "Txtuserid" runat= "Server" ></asp:TextBox>

1. $ ("#<%=txtuserid.clientid%>"). Val ();

2. $ ("Input[id*=txtuserid]"). Val ();

3. $ ("*[id$=txtuserid]"). Val ();

Two jquery methods to get control values

Take value:

$ ("") is a jquery object, not a DOM element
Value is a property of DOM element
jquery corresponds to Val.
Val (): Gets the current value of the first matching element.
Val (val): Sets the value of each matching element.
So the code should write this:
Value: val = $ ("#id") [0].value;
Assign value:
$ ("#id") [0].value = "New value";
or $ ("#id"). Val ("new value");

Or this can also be: val = $ ("#id"). attr ("value");
Gets the value of a set of radio selected items

var item = $ (' input[@name =items][@checked] '). Val ();
Gets the text of the Select selected item
var item = $ ("select[@name =items] option[@selected]"). Text ();
The second element of the Select Drop-down box is the currently selected value
$ (' #select_id ') [0].selectedindex = 1;
Radio the second element of a radio group is the currently selected value
$ (' input[@name =items] '). Get (1). checked = true;

Get Value:

text box, text area: $ ("#txt"). attr ("value");
Multiple-selection box checkbox:$ ("#checkbox_id"). attr ("value");
Radio Group Radio: $ ("input[@type =radio][@checked]"). Val ();
Dropdown box Select: $ (' #sel '). Val ();

Control form elements:
text box, text area: $ ("#txt"). attr ("Value", "");/empty content
$ ("#txt"). attr ("value", ' 11 ');//fill content

Multi-Marquee checkbox: $ ("#chk1"). attr ("Checked", "");/no tick.
$ ("#chk2"). attr ("Checked", true);/tick
if ($ ("#chk1"). attr (' checked ') ==undefined)//judge whether it has been ticked

single-select group radio: $ ("input[@type =radio]"). attr ("Checked", ' 2 ');//Set value=2 project is currently selected
Dropdown Box select: $ ("#sel"). attr ("value", '-sel3 ');//Set VALUE=-SEL3 item as current selection
$ ("<option value= ' 1 ' >1111</option><option value= ' 2 ' >2222</option>"). Appendto ("#sel")// Option to add a drop-down box

$ ("#sel"). empty ();//Empty Drop-down box

Three jquery methods to gain control DropDownList value

Copy Code code as follows:

<script type= "Text/javascript" >
function Bbok ()
{
var a = $ ("#ddlGuo option:selected"). Val ();
var B = $ ("#ddlGuo option:selected"). Text ();
$ ("#txttext"). attr ("value", b);
$ ("#txtval"). attr ("value", a);
}
</script>
<asp:dropdownlist id= "Ddlguo" runat= "Server" >
<asp:listitem selected= "True" value= "001" > Beijing </asp:ListItem>
<asp:listitem value= "> Nanjing </asp:ListItem>
<asp:listitem value= "313" > Suzhou </asp:ListItem>
</asp:DropDownList>
<asp:textbox id= "txtval" runat= "Server" ></asp:TextBox>
<asp:textbox id= "Txttext" runat= "Server" ></asp:TextBox>
<br/>
<asp:button id= "Button1" runat= "Server" text= "click Select" onclientclick= "Bbok ();"/>