如果清空所有复选框但运行插入查询并插入数据，这会给我错误 msg

Question

function checkbox() {
// body...
var a = document.getElementsByName('proinf[]');
for (var i = 0; i < a.length; i++) {
if (a[i].checked == true) {
document.getElementById("error_checkbox").innerHTML = "";
return true;
}else {
document.getElementById("error_checkbox").innerHTML = "* Please Checked Atleast 1 Professional Skill";
}
}
}

<input id="sbmtbtn" type="Submit" class="btn btn-primary"    onclick="return checkbox()" name="Submit" value="Submit">

Answer 1

Try this----
function checkbox() {
// body...
var ischecked=false;
var a = document.getElementsByName('proinf[]');
for (var i = 0; i < a.length; i++) {
if (a[i].checked == true) {
ischecked=true;
}
}   
if(ischecked===true){
document.getElementById("error_checkbox").innerHTML = "";
return true;
}
else{
document.getElementById("error_checkbox").innerHTML = "* Please Checked Atleast 1 Professional Skill";
return false;
}
}