function selectAll(obj) {//本函数实现将gridview中本页内实现全选
    var theTable = obj.parentNode.parentNode.parentNode;
    var inputs = theTable.getElementsByTagName("input");
    for (var i = 0; i < inputs.length; i++) {
        if (inputs[i].type != "checkbox") continue;
        inputs[i].checked = obj.checked;
    }
}
function selectitem() {//本函数实现将gridview中本页内实现全选
    var checkbox = document.getElementsByTagName("input");
    if (checkbox[0].checked == true) {
        for (var i = 0; i < checkbox.length; i++)
            checkbox[i].checked = false;
    }
    else {
        for (var i = 0; i < checkbox.length; i++)
            checkbox[i].checked = true;
    }

}