javascript - 固定字数限制后如何更改文本颜色

Question

我必须在固定的字符限制后更改我的 contenteditable 元素文本颜色，我应该怎么做。就像 140 个字符之前的文本将是黑色的，但在 140 个字符之后，将写入的任何文本都会自动变为红色。

function setEndOfContenteditable(contentEditableElement) {
    var range, selection;
    range = document.createRange(); //Create a range (a range is a like the selection but invisible)
    range.selectNodeContents(contentEditableElement); //Select the entire contents of the element with the range
    range.collapse(false); //collapse the range to the end point. false means collapse to end rather than the start
    selection = window.getSelection(); //get the selection object (allows you to change selection)
    selection.removeAllRanges(); //remove any selections already made
    selection.addRange(range); //make the range you have just created the visible selection
}

elem = document.getElementById('my-content');

elem.addEventListener("keypress", function(evt) {
    var _evt = evt;
    setTimeout(function() {
        _evt = _evt || window.event;
        var charCode = _evt.keyCode || _evt.which;
        $("#my-content").lettering('words');
        setEndOfContenteditable(elem);
    }, 10, _evt);
}, false);

Answer 1

检查输入的长度，如果它高于你想要的，改变颜色:

if (elem.value.length > 140) {
    elem.style.color = 'red';
} else {
    elem.style.color = 'black';
}

我不是很理解这个问题，但希望对您有所帮助。