Limiting how many checkboxes can be checked in Powermail Typo3

Question

有没有一种方法可以限制可以在Powermail表单（Typo3 v7）中选中的复选框？

Answer 1

We have to write our own validator. Typo3 add some variables within name attribute and this variable has to be read out. It looks like this:

name="tx_powermail_pi1[field][variable][]

Below an example with jquery.

$("input[name*='variable']").change(function(){
    var max= 3;
    if( $("input[name*='variable']:checked").length == max ){
        $("input[name*='variable']").attr('disabled', 'disabled');
        $("input[name*='variable']:checked").removeAttr('disabled');
    }else{
        $("input[name*='variable']").removeAttr('disabled');
    }
});

More info https://docs.typo3.org/typo3cms/extensions/powermail/ForDevelopers/WriteOwnValidators/Index.html