JavaScript以防止在n utf 8个字符后写入表单元素 [英] javascript to prevent writing into form elements after n utf 8 characters
问题描述
我为我的数据库，表格和表格行使用了 utf8_unicode_ci 排序规则。 我的网站语言不常见字符如ş，Ğ，ö，ü，ç，İ
我有服务器端验证&验证规则，但为了访问者的舒适度，我想使用一个javascript代码：
1 - ）防止在<$ c之后写入表单输入$ c> n utf8 字符，同时实现实时倒计时。
2 - ）我需要轻松地填充javascript函数，因为不同的表单输入在同一个html页面中具有不同的
我搜索了我的目标，不幸的是我只能从下面给出的SO中找到一个部分的东西（在textarea中使用javascript计算字节数）
它计算textarea在UTF8时的字节长度。
getUTF8Length：function（string）{
var utf8length = 0;
for（var n = 0; n
if（c <128）{
utf8length ++; （（c> 127）&&（c< 2048））{
utf8length = utf8length + 2;
}
}
else {
utf8length = utf8length + 3;
}
}
return utf8length;
}
我也在 http://jsbin.com/fafonimo/3/edit ，这也在下面给出（一些回答者可能想要利用）：
HTML
< ;！DOCTYPE html>
< html>
< head>
< meta charset =utf-8>
< title> JS Bin< / title>
< / head>
< body>
< form method =postaction =＃>
<！ - FıstıkçıŞahapöğlenülüküsüçerçöp - >
<！ - - 35个字符以上 - >
< label class =c1for =id-input>作者姓名< / label>
< input class =c1type =textid =id-inputname =author>
< input class =c1type =submitvalue =Send>
< / form>
< / body>
< / html>
CSS
.c1 {width：80％;行高：1em的;填充：1em; margin：1em 10％;}
这绝对不是我对PHP或MySQL的态度，直接请求解决方案代码抱歉。
关于
I在这里找到答案 http://jsfiddle.net/67XDq/7/
问候
HTML
< tr id =rq17>
< td class ='qnum'> 17.< / td>
< td class ='qtext'>问题？ < i>最多500个字符 - < input style =color：red; font-size：12pt; font-style：italic; readonly type =textid ='q17length'name =q17lengthsize =3maxlength =3value =500> < / i>< br />< textarea onKeyDown =textCounter（this，500）;
onKeyUp =textCounter（this，'q17length'，500）class =scanwidname =q17id =q17rows =5cols =>< / textarea><< / ; / TD>
< / tr>
JS
function textCounter（field，cnt，maxlimit）{
var cntfield = document.getElementById（cnt）
if（field.value.length> maxlimit）// if too long ...修剪它！
field.value = field.value.substring（0，maxlimit）;
//否则，更新'剩下的字符'counter
else
cntfield.value = maxlimit - field.value.length;
}
I use utf8_unicode_ci collation for my database, tables and table rows.
My site language will have uncommon characters like ş, Ğ, ö, ü, ç, İ
I have server side verification & validation rules however for visitor comfort, I want to use a javascript code that:
1-) prevent writing into form input after n utf8 characters while achieving a live countdown.
2-) I need to easily populate the javascript function since different form inputs have different values of n in the same html page
I searched for my aim and unfortunately I only could find a partial thingy from SO given below (Count bytes in textarea using javascript)
it counts how long in bytes a textarea is when UTF8.
getUTF8Length: function(string) {
var utf8length = 0;
for (var n = 0; n < string.length; n++) {
var c = string.charCodeAt(n);
if (c < 128) {
utf8length++;
}
else if((c > 127) && (c < 2048)) {
utf8length = utf8length+2;
}
else {
utf8length = utf8length+3;
}
}
return utf8length;
}
I also created a sample and simple HTML 5 form on http://jsbin.com/fafonimo/3/edit which is given below also (some answerers may want to utilize):
HTML
<!DOCTYPE html>
<html>
<head>
<meta charset="utf-8">
<title>JS Bin</title>
</head>
<body>
<form method="post" action="#">
<!--Fıstıkçı Şahap öğlen ülüküsü çerçöp-->
<!--35 characters above-->
<label class="c1" for="id-input">NAME OF THE AUTHOR</label>
<input class="c1" type="text" id="id-input" name="author">
<input class="c1" type="submit" value="Send">
</form>
</body>
</html>
CSS
.c1 {width:80%; line-height:1em; padding:1em;margin:1em 10%;}
it's absolutely not my attitude for PHP or MySQL however sorry for requesting the solution code directly.
regards
I found the answer here http://jsfiddle.net/67XDq/7/
regards
HTML
<tr id="rq17">
<td class='qnum'>17.</td>
<td class='qtext'>Questions? <i>Maximum of 500 characters - <input style="color:red;font-size:12pt;font-style:italic;" readonly type="text" id='q17length' name="q17length" size="3" maxlength="3" value="500"> characters left</i><br/><textarea onKeyDown="textCounter(this,500);"
onKeyUp="textCounter(this,'q17length' ,500)" class="scanwid" name="q17" id="q17" rows="5" cols=""></textarea></td>
</tr>
JS
function textCounter(field,cnt, maxlimit) {
var cntfield = document.getElementById(cnt)
if (field.value.length > maxlimit) // if too long...trim it!
field.value = field.value.substring(0, maxlimit);
// otherwise, update 'characters left' counter
else
cntfield.value = maxlimit - field.value.length;
}
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