function hasClass( elem, cls ) {
var reClass = new RegExp(' ' + cls + ' ');
return reClass.test(' ' + elem.className + ' ');
}
i am a new learner of javascript, i saw the above function from a book.but i don't what's the meaning of it? expect someone can explain it to me.many thanks.
It's just testing whether a given element contains a given class. This is useful for elements with multiple classes (older browsers don't support that by default).
Consider an element like <div id='test' class="button login"></div>
. If you pass that to the function, you'll get as follows:
function hasClass( elem, cls ) {
// var reClass = new RegExp(' login ');
var reClass = new RegExp(' ' + cls + ' ');
// return reClass.test(' button login '); (ie, true)
return reClass.test(' ' + elem.className + ' ');
}
console.log(hasClass(document.getElementById('test'), 'login'));
它检查元素的class属性是否包含指定的类(cls)
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