问如何在没有jQuery的情况下应用“：without”选择器？

EN

var divs= document.getElementsByTagName('div');
var len = divs.length;
for (var i = 0; i < len; i++) {
    if(divs[i].innerHTML.indexOf("John") != -1) {
        divs[i].className += " underline"
    }
}

.underline{
   text-decoration: underline;
}

var elements = document.getElementsByTagName("div");
for (var i=0;i<elements.length;i++) {
    var elem = elements[i];
    if (elem.innerHTML.indexOf("John") != -1) {
        // do whatever you plan to do
    }
}

var allDivs = document.querySelectorAll('div');

[].forEach.call(allDivs, function(a){
    if (a.textContent.indexOf('John') !== -1){
        a.style.textDecoration = 'underline';
    }
});

var allDivs = document.querySelectorAll('div');

[].forEach.call(allDivs, function(a){
    if (/\bjohn\b/i.test(a.textContent)){
        a.style.textDecoration = 'underline';
    }
});

var allDivs = document.querySelectorAll('div');

[].forEach.call(allDivs, function(a){
    if (/\bjohn\b/i.test(a.textContent)){
        a.classList.add('underlined');
    }
});

var allDivs = document.querySelectorAll('div');

[].forEach.call(allDivs, function (a) {
    if (/\bjohn\b/gi.test(a.textContent)) {
        a.innerHTML = a.innerHTML.replace(/(\bjohn\b)/gi, '<span class="underlined">$1</span>');
    }
});