<script type="text/javascript">
    $(document).ready(function () {
        $('.selecctall').click(function (event) {
            if (this.checked) {
                $('.checkbox1').each(function () {
                    this.checked = true;
                });
            } else {
                $('.checkbox1').each(function () {
                    this.checked = false;
                });
            }
        });

    });

</script>

Javascript:

// Check
document.getElementById("checkbox").checked = true;

// Uncheck
document.getElementById("checkbox").checked = false;

jQuery 1.6 (+):

// Check
$("#checkbox").prop("checked", true);

// Uncheck
$("#checkbox").prop("checked", false);

jQuery (1.5 -):

// Check
$("#checkbox").attr("checked", true);

// Uncheck
$("#checkbox").attr("checked", false);

使用vanilla js:

//for one element: 
document.querySelector('.myCheckBox').checked = true  //will select the first matched element
document.querySelector('.myCheckBox').checked = false//will unselect the first matched element

//for multiple elements:
for (const checkbox of document.querySelectorAll('.myCheckBox')) {
//iterating over all matched elements

checkbox.checked = true //for selection
checkbox.checked = false //for unselection
}

试试这个:

//Check
document.getElementById('checkbox').setAttribute('checked', 'checked');

//UnCheck
document.getElementById('chk').removeAttribute('checked');

检查:

document.getElementById("id-of-checkbox").checked = true;

取消:

document.getElementById("id-of-checkbox").checked = false;

<script type="text/javascript">
    $(document).ready(function () {
        $('.selecctall').click(function (event) {
            if (this.checked) {
                $('.checkbox1').each(function () {
                    this.checked = true;
                });
            } else {
                $('.checkbox1').each(function () {
                    this.checked = false;
                });
            }
        });

    });

</script>