【转载】 input 和 textarea 最大文字限定插件

最新推荐文章于 2025-09-12 14:04:02 发布

转载最新推荐文章于 2025-09-12 14:04:02 发布 · 63 阅读

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原文链接：http://www.cnblogs.com/fx2008/archive/2011/12/22/2298279.html

文章标签：

#javascript #ViewUI

该插件为输入框和文本区域提供字符计数和限制功能，支持中文一个字符计算为1，英文字符计算为0.5，并提供字符删除效果。

/* input 和 textarea 最大文字限定插件 
 * 修改版, 一个中文表示1一个字, 一个英文半个字; 
 * TextLimit - jQuery plugin for counting and limiting characters for input and textarea fields 
 *  
 * pass '-1' as speed if you don't want the char-deletion effect. (don't just put 0) 
 * Example: jQuery("Textarea").textlimit('span.counter',256) 
 * 
 * $Version: 2009.07.25 +r2 
 * Copyright (c) 2009 Yair Even-Or 
 * vsync.design@gmail.com 
*/
;  
String.prototype.getBytes = function () { 
    var cArr = this.match(/[^\x00-\xff]/ig); 
    return this.length + (cArr == null ? 0 : cArr.length); 
}; 
(function(jQuery) { 
    jQuery.fn.textlimit=function(counter_el, thelimit, speed) { 
        var charDelSpeed = speed || 15; 
        var toggleCharDel = speed != -1; 
        var toggleTrim = true; 
        var that = this[0]; 
        var isCtrl = false;  
        updateCounter(); 
          
        function updateCounter(){ 
            if(typeof that == "object") 
                jQuery(counter_el).text(thelimit - Math.ceil(that.value.getBytes()/2)); 
        }; 
          
        this.keydown (function(e){  
            if(e.which == 17) isCtrl = true; 
            var ctrl_a = (e.which == 65 && isCtrl == true) ? true : false; // detect and allow CTRL + A selects all. 
            var ctrl_v = (e.which == 86 && isCtrl == true) ? true : false; // detect and allow CTRL + V paste. 
            // 8 is 'backspace' and 46 is 'delete' 
            if( this.value.length >= thelimit && e.which != '8' && e.which != '46' && ctrl_a == false && ctrl_v == false) 
                e.preventDefault(); 
        }) 
        .keyup (function(e){ 
            updateCounter(); 
            if(e.which == 17) 
                isCtrl=false; 
  
            if( this.value.length >= thelimit && toggleTrim ){ 
                if(toggleCharDel){ 
                    // first, trim the text a bit so the char trimming won't take forever 
                    // Also check if there are more than 10 extra chars, then trim. just in case. 
                    if ( (this.value.length - thelimit) > 10 ) 
                        that.value = that.value.substr(0,thelimit+100); 
                    var init = setInterval 
                        (  
                            function(){  
                                if( that.value.length <= thelimit ){ 
                                    init = clearInterval(init); updateCounter()  
                                } 
                                else{ 
                                    // deleting extra chars (one by one) 
                                    that.value = that.value.substring(0,that.value.length-1); jQuery(counter_el).text(Math.ceil(that.value.getBytes()/2)); 
                                } 
                            } ,charDelSpeed  
                        ); 
                } 
                else this.value = that.value.substr(0,thelimit); 
            } 
        }); 
          
    }; 
})(jQuery);