var a = document.querySelector(\'a\');
a.onclick = function(e) {
e.preventDefault();
}
阻止冒泡事件
<div class="father">
<div class="son"></div>
</div>
<script>
var son = document.querySelector(\'.son\');
son.addEventListener(\'click\', function(e) {
alert(\'son\');
e.stopPropagation();
}, false)