全选

$("#selectAll").click(function(){
$("input[name='offer_list_ck']").prop("checked", $(this).prop('checked'));
});

function checkCheckbox(){
$("input[name='offer_list_ck']").unbind().click(function(){
var childCheckBox = $("input[name='offer_list_ck']");
var checkedBox = $("input[name='offer_list_ck']:checked");
if(childCheckBox.length == checkedBox.length){
$("#selectAll").prop("checked",true);
}else{
$("#selectAll").prop("checked",false);
}
});

}