字符串trim()的使用

示例一:

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<head>
  <title>测试JS扩展方法</title>
  <script type="text/javascript">
    // 合并多个空白为一个空白
    String.prototype.ResetBlank = function() {    //对字符串扩展
      var regEx = /s+/g;
      return this.replace(regEx, ' ');
    };
 
    window.onload = function()
    {
      var str = "你   在他想还好吗?";
      alert(str);
      str = str.ResetBlank();    //这样就能够调用了,跟C#的很像吧!
      alert(str);
    }
  </script>
</head>

示例二:

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// 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.GetCN = function() {
  var regEx = /[^u4e00-u9fa5uf900-ufa2d]/g;
  return this.replace(regEx, '');
};
  
// String转化为Number
String.prototype.ToInt = function() {
  return isNaN(parseInt(this)) ? this.toString() : parseInt(this);
};
  
// 得到字节长度
String.prototype.GetLen = function() {
  var regEx = /^[u4e00-u9fa5uf900-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;
  }
};
  
// 获取文件全名
String.prototype.GetFileName = function() {
  var regEx = /^.*/([^/?]*).*$/;
  return this.replace(regEx, '$1');
};
  
// 获取文件扩展名
String.prototype.GetExtensionName = function() {
  var regEx = /^.*/[^/]*(.[^.?]*).*$/;
  return this.replace(regEx, '$1');
};
  
//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);
  }
};
//格式化字符串 add By 刘景宁 2010-12-09 
String.Format = function() {
  if (arguments.length == 0) {
    return '';
  }
  
  if (arguments.length == 1) {
    return arguments[0];
  }
  
  var reg = /{(d+)?}/g;
  var args = arguments;
  var result = arguments[0].replace(reg, function($0, $1) {
    return args[parseInt($1) + 1];
  });
  return result;
};
  
// 数字补零
Number.prototype.LenWithZero = function(oCount) {
  var strText = this.toString();
  while (strText.length < oCount) {
    strText = '0' + strText;
  }
  return strText;
};
  
// Unicode还原
Number.prototype.ChrW = function() {
  return String.fromCharCode(this);
};
  
// 数字数组由小到大排序
Array.prototype.Min2Max = function() {
  var oValue;
  for (var i = 0; i < this.length; i++) {
    for (var j = 0; j <= i; j++) {
      if (this[i] < this[j]) {
        oValue = this[i];
        this[i] = this[j];
        this[j] = oValue;
      }
    }
  }
  return this;
};
  
// 数字数组由大到小排序
Array.prototype.Max2Min = function() {
  var oValue;
  for (var i = 0; i < this.length; i++) {
    for (var j = 0; j <= i; j++) {
      if (this[i] > this[j]) {
        oValue = this[i];
        this[i] = this[j];
        this[j] = oValue;
      }
    }
  }
  return this;
};
  
// 获得数字数组中最大项
Array.prototype.GetMax = function() {
  var oValue = 0;
  for (var i = 0; i < this.length; i++) {
    if (this[i] > oValue) {
      oValue = this[i];
    }
  }
  return oValue;
};
  
// 获得数字数组中最小项
Array.prototype.GetMin = function() {
  var oValue = 0;
  for (var i = 0; i < this.length; i++) {
    if (this[i] < oValue) {
      oValue = this[i];
    }
  }
  return oValue;
};
  
// 获取当前时间的中文形式
Date.prototype.GetCNDate = function() {
  var oDateText = '';
  oDateText += this.getFullYear().LenWithZero(4) + new Number(24180).ChrW();
  oDateText += this.getMonth().LenWithZero(2) + new Number(26376).ChrW();
  oDateText += this.getDate().LenWithZero(2) + new Number(26085).ChrW();
  oDateText += this.getHours().LenWithZero(2) + new Number(26102).ChrW();
  oDateText += this.getMinutes().LenWithZero(2) + new Number(20998).ChrW();
  oDateText += this.getSeconds().LenWithZero(2) + new Number(31186).ChrW();
  oDateText += new Number(32).ChrW() + new Number(32).ChrW() + new Number(26143).ChrW() + new Number(26399).ChrW() + new String('26085199682010819977222352011620845').substr(this.getDay() * 5, 5).ToInt().ChrW();
  return oDateText;
};
//扩展Date格式化
Date.prototype.Format = function(format) {
  var o = {
    "M+": this.getMonth() + 1, //月份     
    "d+": this.getDate(), //日     
    "h+": this.getHours() % 12 == 0 ? 12 : this.getHours() % 12, //小时     
    "H+": this.getHours(), //小时     
    "m+": this.getMinutes(), //分     
    "s+": this.getSeconds(), //秒     
    "q+": Math.floor((this.getMonth() + 3) / 3), //季度     
    "S": this.getMilliseconds() //毫秒     
  };
  var week = {
    "0": "u65e5",
    "1": "u4e00",
    "2": "u4e8c",
    "3": "u4e09",
    "4": "u56db",
    "5": "u4e94",
    "6": "u516d"
  };
  if (/(y+)/.test(format)) {
    format = format.replace(RegExp.$1, (this.getFullYear() + "").substr(4 - RegExp.$1.length));
  }
  if (/(E+)/.test(format)) {
    format = format.replace(RegExp.$1, ((RegExp.$1.length > 1) ? (RegExp.$1.length > 2 ? "u661fu671f" : "u5468") : "") + week[this.getDay() + ""]);
  }
  for (var k in o) {
    if (new RegExp("(" + k + ")").test(format)) {
      format = format.replace(RegExp.$1, (RegExp.$1.length == 1) ? (o[k]) : (("00" + o[k]).substr(("" + o[k]).length)));
    }
  }
  return format;
}
Date.prototype.Diff = function(interval, objDate) {
  //若参数不足或 objDate 不是日期类型則回传 undefined
  if (arguments.length < 2 || objDate.constructor != Date) { return undefined; }
  switch (interval) {
    //计算秒差                            
    case 's': return parseInt((objDate - this) / 1000);
      //计算分差
    case 'n': return parseInt((objDate - this) / 60000);
      //计算時差
    case 'h': return parseInt((objDate - this) / 3600000);
      //计算日差
    case 'd': return parseInt((objDate - this) / 86400000);
      //计算周差
    case 'w': return parseInt((objDate - this) / (86400000 * 7));
      //计算月差
    case 'm': return (objDate.getMonth() + 1) + ((objDate.getFullYear() - this.getFullYear()) * 12) - (this.getMonth() + 1);
      //计算年差
    case 'y': return objDate.getFullYear() - this.getFullYear();
      //输入有误
    default: return undefined;
  }
};
  
//检测是否为空
Object.prototype.IsNullOrEmpty = function() {
  var obj = this;
  var flag = false;
  if (obj == null || obj == undefined || typeof (obj) == 'undefined' || obj == '') {
    flag = true;
  } else if (typeof (obj) == 'string') {
    obj = obj.trim();
    if (obj == '') {//为空
      flag = true;
    } else {//不为空
      obj = obj.toUpperCase();
      if (obj == 'NULL' || obj == 'UNDEFINED' || obj == '{}') {
        flag = true;
      }
    }
  }
  else {
    flag = false;
  }
  return flag;
原文地址:https://www.cnblogs.com/jxl-blog/p/6618784.html