A problem encountered during development recently is that the customer requires no more options, but these projects can only select 2 items at most. If you select more than 2 items, you are prompted to choose to delete one of them randomly. I found a lot on the Internet Article No instance is found. Therefore, I have worked hard to write a new one and share it with you. I'm a cainiao! Hope experts can give more valuable comments
In fact, the first step is checkboxlisttext. aspx.
<Head>
<Title> checkboxlist instance </title>
</Head>
<Script language = "JavaScript">
Function setcheckboxstate (STR)
{
O = Document. getelementsbytagname ("input ")
// O = from1.cbyyjslscly;
Var val = 0;
For (I = 0; I <O. length; I ++)
{
If (O [I]. type = "checkbox" & O [I]. Checked & O [I]. Name = Str)
{
// Alert (O [I]. value)
Val = Val + 1;
}
If (Val> 2)
{
Alert ('the project you selected can only be within two! ')
O [I]. Checked = false;
Return;
}
}
// Alert (VAL)
}
</SCRIPT>
</Head>
<Body ms_positioning = "gridlayout">
<Form ID = "form1" method = "Post" runat = "server">
<Asp: checkboxlist id = "checkboxlist1" runat = "server">
<Asp: listitem value = "Net"> net </ASP: listitem>
<Asp: listitem value = "Java"> JAVA </ASP: listitem>
<Asp: listitem value = "VB"> VB </ASP: listitem>
</ASP: checkboxlist>
</Form>
</Body>
</Html>
Then there is the background management File
Checkboxlist1.attributes. Add ("onclick", "setcheckboxstate ('checkboxlist1 ');");
OK!
