常用js 扩展

// 替换所有String.prototype.replaceAll = function(reallyDo, replaceWith, ignoreCase) {if (!RegExp.prototype.isPrototypeOf(reallyDo)) {return this.replace(new RegExp(reallyDo, (ignoreCase ? "gi" : "g")),replaceWith);} else {return this.replace(reallyDo, replaceWith);}};// 清除两边的空格  String.prototype.trim = function() {return this.replace(/(^\s*)|(\s*$)/g, '');};// 合并多个空白为一个空白String.prototype.resetBlank = function() {var regEx = /\s+/g;return this.replace(regEx, ' ');};// 保留数字String.prototype.getNum = function() {var regEx = /[^\d]/g;return this.replace(regEx, '');};// 保留中文String.prototype.getChinese = function() {var regEx = /[^\u4e00-\u9fa5\uf900-\ufa2d]/g;return this.replace(regEx, '');};// String转化为NumberString.prototype.toInt = function() {return isNaN(parseInt(this)) ? this.toString() : parseInt(this);};String.prototype.toFloat = function() {return isNaN(parseFloat(this)) ? this.toString() : parseFloat(this);};// 得到字节长度String.prototype.getLength = function() {var regEx = /^[\u4e00-\u9fa5\uf900-\ufa2d]+$/;if (regEx.test(this)) {return this.length * 2;} else {var oMatches = this.match(/[\x00-\xff]/g);var oLength = this.length * 2 - oMatches.length;return oLength;}};