在使用javascript删除确认消息之前，检查是否选中复选框

我想确保用户在使用javascript获取删除确认消息之前选中了复选框。有人能告诉我如何做到这一点吗

小提琴：

HTML

<form name="deleteFiles" action="" method="post" >
    <input type='checkbox' name='files' id='1' onsubmit="return confirm_update();" value='1' /> file 1<br>

    <input type="submit" value="Submit" name="submit">

</form>

---

onsubmit

操作应该在

表单上，而不是在
复选框上

其次，您的
checkbox
元素被分配给变量
arrcheckbox
，而在
if
循环中，您使用
checkb
进行检查

修改后的代码如下：

HTML:

<form name="deleteFiles" action="" method="post" onsubmit="return confirm_update();">
    <input type='checkbox' name='files' id='1' value='1' />file 1
    <br>
    <input type="submit" value="Submit" name="submit">
</form>

function confirm_update() {
    var arrCheckboxes = document.deleteFiles.elements["files"];
    if (arrCheckboxes.checked != true) {
        alert("You do not have any selected files to delete.");
        return false;

    } else {
        return confirm("Are you sure you want to proceed deleting the selected   files?");
    }
}

<form name="deleteFiles" action="" method="post" onsubmit="return confirm_update();">
    <input type='checkbox' name='files' id='1' value='1' />file 1
    <input type='checkbox' name='files' id='2' value='2' />file 2
    <br>
    <input type="submit" value="Submit" name="submit">
</form>

function confirm_update() {
    var chkCount = 0;
    var arrCheckboxes = document.deleteFiles.elements["files"];
    for (var i=0; i<arrCheckboxes.length; i++) {
        if(arrCheckboxes[i].checked == true) {
            chkCount++;
        }
    }
    if (chkCount === 0) {
        alert("You do not have any selected files to delete.");
        return false;
    } else {
        return confirm("Are you sure you want to proceed deleting the selected   files?");
    }
}

编辑：如果您的表单有多个
复选框
字段，并且您只想在未选中任何字段时抛出错误（我认为您需要）。您可以按如下方式进行操作：

HTML:

<form name="deleteFiles" action="" method="post" onsubmit="return confirm_update();">
    <input type='checkbox' name='files' id='1' value='1' />file 1
    <br>
    <input type="submit" value="Submit" name="submit">
</form>

function confirm_update() {
    var arrCheckboxes = document.deleteFiles.elements["files"];
    if (arrCheckboxes.checked != true) {
        alert("You do not have any selected files to delete.");
        return false;

    } else {
        return confirm("Are you sure you want to proceed deleting the selected   files?");
    }
}

<form name="deleteFiles" action="" method="post" onsubmit="return confirm_update();">
    <input type='checkbox' name='files' id='1' value='1' />file 1
    <input type='checkbox' name='files' id='2' value='2' />file 2
    <br>
    <input type="submit" value="Submit" name="submit">
</form>

function confirm_update() {
    var chkCount = 0;
    var arrCheckboxes = document.deleteFiles.elements["files"];
    for (var i=0; i<arrCheckboxes.length; i++) {
        if(arrCheckboxes[i].checked == true) {
            chkCount++;
        }
    }
    if (chkCount === 0) {
        alert("You do not have any selected files to delete.");
        return false;
    } else {
        return confirm("Are you sure you want to proceed deleting the selected   files?");
    }
}


文件1
文件2



JS:

<form name="deleteFiles" action="" method="post" onsubmit="return confirm_update();">
    <input type='checkbox' name='files' id='1' value='1' />file 1
    <br>
    <input type="submit" value="Submit" name="submit">
</form>

function confirm_update() {
    var arrCheckboxes = document.deleteFiles.elements["files"];
    if (arrCheckboxes.checked != true) {
        alert("You do not have any selected files to delete.");
        return false;

    } else {
        return confirm("Are you sure you want to proceed deleting the selected   files?");
    }
}

<form name="deleteFiles" action="" method="post" onsubmit="return confirm_update();">
    <input type='checkbox' name='files' id='1' value='1' />file 1
    <input type='checkbox' name='files' id='2' value='2' />file 2
    <br>
    <input type="submit" value="Submit" name="submit">
</form>

function confirm_update() {
    var chkCount = 0;
    var arrCheckboxes = document.deleteFiles.elements["files"];
    for (var i=0; i<arrCheckboxes.length; i++) {
        if(arrCheckboxes[i].checked == true) {
            chkCount++;
        }
    }
    if (chkCount === 0) {
        alert("You do not have any selected files to delete.");
        return false;
    } else {
        return confirm("Are you sure you want to proceed deleting the selected   files?");
    }
}

功能确认\u更新（）{
var chkCount=0；
var arrcheckbox=document.deleteFiles.elements[“files”]；
对于（var i=0；i
为什么您的
提交
在
复选框
中，而不是在
表单
中？因为我的原始代码上有其他具有不同名称的复选框，所以我更感兴趣的是知道如何在复选框级别执行此操作。如果可能的话