[Original] implementation of the checkbox "select all" and "cancel all" operations on the page (JavaScript)

During Web development, you often need to select and cancel all checkpoints on the page.

HTML code of the page

<Input type = 'checkbox' name = 'info' value = 'A'>
<Input type = 'checkbox' name = 'info' value = 'B'>
<Input type = 'checkbox' name = 'info' value = 'C'>
<Input type = 'checkbox' name = 'info' value = 'D'>
<Input type = 'checkbox' name = 'info' value = 'E'>
<Br/>
<Input type = 'button 'value = 'select all 'onclick = 'check _ all ();'>
<Input type = 'button 'value = 'cancel all 'onclick = 'check _ all_un ();'>

Corresponding JavaScript code

<Script>
Function check_all ()
{// Select all
Arr = document. getElementsByName ('info ');
For (I = 0; I <arr. length; I ++)
{
Arr [I]. checked = true;
}
}

Function check_all_un ()
{// Cancel all
Arr = document. getElementsByName ('info ');
For (I = 0; I <arr. length; I ++)
{
Arr [I]. checked = false;
}
}
</Script>