jquery如何判断checkbox（复选框）是否被选中
谁都知道 在html 如果一个复选框被选中 是 checked="checked"。
但是我们如果用jquery alert($("#id").attr("checked")) 会提示您是true而不是checked
所以很多朋友判断 if($("#id").attr("checked")=="true") 这个是错误的，其实应该是 if($("#id").attr("checked")==true)
例子里面包括了一下几个功能。
<input type="button" id="btn1" value="全选">
<input type="button" id="btn2" value="取消全选">
<input type="button" id="btn3" value="选中所有奇数">
<input type="button" id="btn4" value="反选">
<input type="button" id="btn5" value="获得选中的所有值">
代码
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN">
<HTML>
<HEAD>
<TITLE> New Document </TITLE>
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8" />
<SCRIPT LANGUAGE="JavaScript" src="http://www.cnjquery.com/demo/jquery.js"></script >
<SCRIPT LANGUAGE="JavaScript">
<!--
$("document").ready(function(){
$("#btn1").click(function(){
$("[name='checkbox']").attr("checked",'true');//全选
})
$("#btn2").click(function(){
$("[name='checkbox']").removeAttr("checked");//取消全选
})
$("#btn3").click(function(){
$("[name='checkbox']:even").attr("checked",'true');//选中所有奇数
})
$("#btn4").click(function(){
$("[name='checkbox']").each(function(){
if($(this).attr("checked"))
{
$(this).removeAttr("checked");
}
else
{
$(this).attr("checked",'true');
}
})
})
$("#btn5").click(function(){
var str="";
$("[name='checkbox'][checked]").each(function(){
str+=$(this).val()+""r"n";
//alert($(this).val());
})
alert(str);
})
})
//-->
</SCRIPT>
</HEAD>
<BODY>
<form name="form1" method="post" action="">
<input type="button" id="btn1" value="全选">
<input type="button" id="btn2" value="取消全选">
<input type="button" id="btn3" value="选中所有奇数">
<input type="button" id="btn4" value="反选">
<input type="button" id="btn5" value="获得选中的所有值">
<br>
<input type="checkbox" name="checkbox" value="checkbox1">
checkbox1
<input type="checkbox" name="checkbox" value="checkbox2">
checkbox2
<input type="checkbox" name="checkbox" value="checkbox3">
checkbox3
<input type="checkbox" name="checkbox" value="checkbox4">
checkbox4
<input type="checkbox" name="checkbox" value="checkbox5">
checkbox5
<input type="checkbox" name="checkbox" value="checkbox6">
checkbox6
<input type="checkbox" name="checkbox" value="checkbox7">
checkbox7
<input type="checkbox" name="checkbox" value="checkbox8">
checkbox8
</form>
/************单个checkbox全选************************/
function clickCheckbox() {
if($("#checkPathAll").attr("checked"))
{
$("input[name='checkPath']").each(function() {
$(this).attr("checked", true);
});
}
else
{
$("input[name='checkPath']").each(function() {
$(this).attr("checked", false);
});
}
}
var dlg;
$( document ).ready( function()
{
// 删除按钮事件开始 ----------------------------------------------------------------------
$("#bottomdelete" ).click( function()
{
var str="";
$("[name='listcheck'][checked]").each(function()
{
if( str == "" )
{
str = $( this ).val();
}
else
{
str += "," + $( this ).val()
}
})
if(str==""||str==null)
{
alert( "请您选择要删除的记录！" );
return false;
}
else
{
if( confirm("您确定要删除所选的理财吗？" ) )
{
document.getElementById("deleteid").value=str;
doSubmit();
}
else
{
$(":check").removeAttr("checked");//取消全选
$( "#bottomSelectAll" ).val( "全选" );
return false;
}
}
}
)
// 删除按钮事件结束 ----------------------------------------------------------------------
// 修改
$( ".update" ).each( function()
{
$( this ).click( function()
{
var moneyArray = $( this ).attr( "accesskey" ).split( ',' );
// $("#firame").attr("src","addMoney.aspx?id="+ moneyArray[0]+"&date="+moneyArray[1]+"&selectType="+moneyArray[3]+"&money="+ moneyArray
[4]+"&comment="+moneyArray[5]+"&inout="+moneyArray[2]+"&userid="+document.getElementById("idHiddle").value)
// var dlg=$("#firame").xDlg(
// {
// pos:{left:"200",top:"400"},
// size:{width:"403px",height:"320px"},
// buttons:null,
// onCancel : function()
// {
// window.location.reload()
// }
//
// });
if(dlg!=null)
{
dlg.close();
}
dlg=$.topWnd().$.xDlg({
pos:"center",
size:{width:"403px",height:"320px"},
buttons:null,
fra:"/pages/mymoney/addMoney.aspx?id="+ moneyArray[0]+"&date="+moneyArray[1]+"&selectType="+moneyArray[3]+"&money="+ moneyArray
[4]+"&comment="+moneyArray[5]+"&inout="+moneyArray[2]+"&userid="+document.getElementById("idHiddle").value,
onCancel : function()
{
window.location.reload()
}
});
dlg.setCaption("修改记录");
dlg.canScroll(false);
}
)
}
)
})
var selectAll = function ( selectid, button )
{
if( button == null )
{
if( $( "#" + selectid + "" ).attr( "checked" ) == true )
{
$("input[name='listcheck']").each(function()
{
$(this).attr("checked", true);
});
}
else
{
$("input[name='listcheck']").each(function()
{
$(this).attr("checked", false);
});
}
}
else
{
if( $( "#" + selectid + "" ).val() == "全选" )
{
$("[name='listcheck']").attr("checked",'true');//全选
$( "#" + selectid + "" ).val( "反选" );
}
else
{
$("[name='listcheck']").removeAttr("checked");//取消全选
$( "#" + selectid + "" ).val( "全选" );
}
}
}
var deleteMoney=function(id)
{
if(confirm("您确定要删除此理财吗？"))
{
document.getElementById("deleteid").value=id;
doSubmit();
}
}
function doSubmit()
{
Form1.submit();
}
var realnumber=function(number)
{
return /^-?\d+(\.\d+)?$/.test(number);
}
function hidenodata()
{
document.getElementById("nodata").style.display="none";
document.getElementById("topfenye").style.display="none";
document.getElementById ("bottomfy").style.display="none";
document.getElementById("zi14").style.display="block";
}
function addClass()
{
if(dlg!=null)
{
dlg.close();
}
var id =document.getElementById("idHiddle").value;
dlg=$.topWnd().$.xDlg({
pos:"center",
size:{width:"403px",height:"320px"},
buttons:null,
fra:"/pages/mymoney/addMoney.aspx?userid=" + id,
onCancel : function()
{
window.location.reload()
}
});
dlg.setCaption("添加记录");
dlg.canScroll(false);
// $("#firame").attr("src","addMoney.aspx?userid=" + id)
//
// dlg=$("#firame").xDlg(
// {
// pos:{left:"200",top:"400"},
// size:{width:"403px",height:"320px"},
// buttons:null ,
// onCancel : function()
// {
// window.location.reload()
// }
// });
// dlg.setCaption("添加记录");
}
function getStringUTFLength(str) {
var value = str.replace(/[^\x00-\xff]/g," ");
return value.length;
}
function leftUTFString(str,len) {
if(getStringUTFLength(str)<=len)
return str;
var value = str.substring(0,len);
while(getStringUTFLength(value)>len) {
value = value.substring(0,value.length-1);
}
return value;
}
function count() {
var value = document.getElementById("comment").value;
value = value.replace(/[\u4e00-\u9fa5]/g," ");
if(value.length>=50) {
with(window.event) {
cancelBubble = true;
keyCode=0;
returnValue = false;
}
document.getElementById("comment").value = leftUTFString(document.getElementById("comment").value,50);
}
}
/*清除*/
function clearfrm()
{
document.all.comment.value="";
document.all.TxbMoney.value="";
return;
}
function subFrm()
{
if (document.all.txdate.value=="")
{
alert("时间不能为空");
document.all.txdate.focus();
return false;
}
if(!CheckDate(document.all.txdate.value))
{
return false;
}
if (document.all.TxbMoney.value=="")
{
alert("金额不能为空");
document.all.TxbMoney.focus();
return false;
}
if (!IsDblNumber(document.all.TxbMoney.value))
{
return false;
}
}
function CheckDate(strDate)
{
var reg=/^(\d{4})([-])(\d{2})([-])(\d{2})/;
if(!reg.test(strDate))
{
alert("时间格式不正确!");
return false;
}
else
{
return true;
}
}
function trim(stringToTrim)
{
return stringToTrim.replace(/^\s+|\s+$/g,"");
}
function IsDblNumber(passedVal)
{
var sign=0;
var flag="￥";
var price;
if (passedVal == ""){return "";}
//if(passedVal=="0"){return "￥00.00";}
for (i=0; i<passedVal.length; i++)
{
if ((passedVal.charAt(i) == ".")||(passedVal.charAt(i) == "．")){i++;sign=sign+1;}
if ((passedVal.charAt(i) == "$")||(passedVal.charAt(i) == "￥")){i++;}
if (passedVal.charAt(i) < "0"){alert("请输入正确的金额");return false;}
if (passedVal.charAt(i) > "9"){alert("请输入正确的金额");return false;}
}
//alert(passedVal);alert(parseInt(passedVal,10));
if(sign>=2){alert("请输入正确的金额");return false;}
if(passedVal.charAt(0) == flag)
price=passedVal.substr(1,passedVal.length-1);
else
price=passedVal.substr(0,passedVal.length);
//alert(price);
if((parseInt(price,10)>9999999)||(parseInt(price,10)<-9999999)){alert("您输入的金额超出范围,金额最大不能超过9999999");return false;}
pricelen=price.length;
dotplace=price.indexOf(".");
//alert(dotplace);
if (dotplace==-1)
{
return(flag+price+".00")
}
if ((pricelen-dotplace)==2)
{
return(flag+price+"0");
}
if ((pricelen-dotplace)>=3)
{
if(parseInt(price.charAt(dotplace+3))>=5)
{
var temp=price.substr(0,dotplace+3)
price=parseFloat(temp)+0.01;
//var NewNumber=New Number(price);
var tempp=price.toString(10)
var dotp=tempp.indexOf(".");
if(dotp==-1)return(flag+tempp+".00");
return(flag+price);
}
return(flag+price.substr(0,dotplace+3))
}
return true;
}
function editClass()
{
var tempUnit ="money";
var id =document.getElementById("addidHiddle").value;
dlg= $.topWnd().$.xDlg(
{
pos : "CENTER",
size :
{
width : "625px", height : "310px"
}
,
fra : "http://www.cnblogs.com/UserControl/Compnent/fenlei.aspx?flag=" + tempUnit + "&id=" + id,
buttons : null , onCancel : function()
{
var html=dlg.body.find("iframe").contents().find("#expose").val();//获取分类
var str= new Array();
var opt="";
str= html.split("#");
if(str.length>0)
{
for(i=str.length-2;i>=0;i--)
{
opt+="<option value='"+str[i].split('|')[0]+"'>"+str[i].split('|')[1]+"</option>"
}
$("#dropType").get(0).options.length = 0; //清空selec
$("#dropType").append(opt);//重新复制
}
}
}
);
dlg.setCaption( "分类管理" );
$.topWnd().dlg=dlg;
}
function ReClose()
{
if(dlg!=null && typeof(dlg.isNull)!="undefined" && !dlg.isNull)dlg.close();
top.frames['mainFra'].location.reload();
}
