//checks all checkboxes
function checkAll(field) {
if (!(field.length)) {
field.checked = true;
}
else {
for (var i = 0; i < field.length; i++) {
field[i].checked = true;
}
}
}
//unchecks all checkboxes
function uncheckAll(field) {
if (!(field.length)) {
field.checked = false;
}
else {
for (var i = 0; i < field.length; i++) {
field[i].checked = false;
}
}
}
<a href="javascript:checkAll(document.FRM.FIELD);">select</a> / <a href="javascript:uncheckAll(document.FRM.FIELD);">deselect</a> all
loop through all checkboxes in a form:
function checkAll() {
for (i=0; i<document.FormName.elements.length; i++) {
if (document.FormName.elements[i].type=="checkbox")
document.FormName.elements[i].checked=true;
}
}