使用jQuery的textarea中的最大长度 [英] Maxlength in textarea using jQuery
问题描述
使用脚本 http://viralpatel.net/blogs/2008/12/set-maxlength-of-textarea-input-using-jquery-javascript.html 我试图将textarea的输入限制为1000个字符.页面中还包括原型.
Using the script off http://viralpatel.net/blogs/2008/12/set-maxlength-of-textarea-input-using-jquery-javascript.html I am trying to limit the input of a textarea to 1000 characters. Prototype is also included in the page.
在chrome中可以正常工作,但在Firefox中会给出以下错误,并且输入不受限制:
It works fine in chrome, but in firefox the following error is given and the input is not limited:
$("textarea[maxlength]") is null
我完全迷住了.任何帮助,将不胜感激.代码段如下.
I'm completely stumped. Any help would be appreciated. The code snippets follow.
文本区域:
<%= text_area 'project', 'description', 'cols' => 60, 'rows' => 8, 'maxlength' => 1000 %>
javascript:
The javascript:
<%= javascript_include_tag "jquery", "jquery.maxlength" -%>
<script type="text/javascript">
jQuery.noConflict();
jQuery(document).ready(function($) {
$().maxlength();
})
</script>
jquery.maxlength.js:
jquery.maxlength.js:
jQuery.fn.maxlength = function(){
$('textarea[maxlength]').keypress(function(event){
var key = event.which;
//all keys including return.
if(key >= 33 || key == 13) {
var maxLength = $(this).attr('maxlength');
var length = this.value.length;
if(length >= maxLength) {
event.preventDefault();
}
}
});
}
推荐答案
将jquery.maxlength.js
文件包装在此文件中:
Wrap your jquery.maxlength.js
file in this:
(function($){
.. existing code goes here
})(jQuery);
当您调用$().maxlength()
时,它试图使用$
变量,但是作用域不同,并且不再等于jQuery
.通过将插件包装在一个自执行的匿名函数中,它将创建一个私有作用域,其中$
= jQuery
When you call $().maxlength()
it is trying to use the $
variable, but in a different scope and it no longer is equal to jQuery
. By wrapping the plugin in a self executing anonymous function, it creates a private scope where $
= jQuery
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