JavaScript implementation Click Select all, again click Cancel Select All

The following are the implementation ideas, have been tested, for reference

var allset = document.getElementById (' Allset '); Get the Select All button element

var a = allset.custom; Custom properties for the Select All button

a = 0; Custom attribute value is 0

var input1 = all.getelementsbytagname (' input '); Get all the input tags under all;

Add Click events to the Select All button to make judgments;

Allset. onclick = function () {

If A is 0, the first for loop is executed;

if (a = = 0) {

Loops through all input tags;

for (i = 0; i < input1.length; i+ +) {

Leave the input label selected (checked = true selected), (checked = False unchecked );

input1[i].checked = true;

The value of the custom property is changed here to 1

a = 1

}

}

// If a for 1 executes the next for loop, leave the input label unchecked

else{

for (i = 0; i < input1.length; i+ +) {

input1[i].checked = false;

A = 0

}

}

}

JavaScript implementation Click Select all, again click Cancel Select All