扩展一个字符自动长度自动检测的函数
/** * 扩展一个字符自动长度自动检测的函数 * @param {[type]} max [description] * @param {Function} callback [description] * @return {[type]} [description] */ jQuery.fn.maxLength = function(max, callback) { this.each(function(){ var type = this.tagName.toLowerCase(); var inputType = this.type ? this.type.toLowerCase() : null; if(type == "input" && inputType == "text" || inputType == "password") { this.maxLength = max; } else if(type == "textarea") { this.onkeypress = function(e) { var obj = e || event; var keyCode = obj.keyCode; var hasSelection = document.selection ? document.selection.createRange().text.length > 0 : this.selectionStart != this.selectionEnd; return !(this.value.length >= max &&(keyCode > 50 || keyCode == 32 || keyCode == 0 || keyCode == 13) && !obj.ctrlKey && !obj.altKey && !hasSelection); }; this.onkeyup = function() { if('undefined' != typeof(callback)) { callback(this.value.length); } if(this.value.length > max) { this.value = this.value.substring(0,max); } }; } }); };