最近在設計寫博客功能時，涉及到留言框輸入字數限制，需要給用戶剩餘數字提示。
參考文章：https://www.cnblogs.com/crazytrip/p/4968230.html
實現效果：
源碼：
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<meta name="viewport" content="width=device-width, initial-scale=1.0">
<meta http-equiv="X-UA-Compatible" content="ie=edge">
<title>統計輸入剩餘字數</title>
</head>
<body>
<div>
<textarea cols="50" rows="5" name="content" id="content" onkeyup="javascript:checkWords(this);"
onmousedown="javascript:checkWords(this);"></textarea>
</div>
<div>
還可以輸入<span style="font-family: Georgia; font-size: 26px;" id="wordCheck">50</span>個漢字
</div>
<script>
var maxstrlen = 50;
function Q(s) {
return document.getElementById(s);
}
function checkWords(c) {
len = maxstrlen;
var str = c.value;
myLen = getStrleng(str);
var wck = Q("wordCheck");
if (myLen > len * 2) {
c.value = str.substring(0, i + 1);
} else {
wck.innerHTML = Math.floor((len * 2 - myLen) / 2);
}
}
function getStrleng(str) {
myLen = 0;
i = 0;
for (; (i < str.length) && (myLen <= maxstrlen * 2); i++) {
if (str.charCodeAt(i) > 0 && str.charCodeAt(i) < 128)
myLen++;
else
myLen += 2;
}
return myLen;
}
</script>
</body>
</html>