jquery 数值输入框实现

页面上引入这段js，监听了文本keyup与blur事件，参照easyui写的，文本框初始化时没做数值验证，有兴趣的人参照下面blur事件实现

<input type="text" class="ll-numberbox" data-options="min:0.1,max:999,precision:2" value="" />

//数值输入框格式化
String.prototype.endWith = function(str) {
  if (str == null || str == "" || this.length == 0 || str.length > this.length)
    return false;
  if (this.substring(this.length - str.length) == str)
    return true;
  else
    return false;
  return true;
}
String.prototype.startWith = function(str) {
  if (str == null || str == "" || this.length == 0 || str.length > this.length)
    return false;
  if (this.substr(0, str.length) == str)
    return true;
  else
    return false;
  return true;
}
String.prototype.trim = function() {
  return this.replace(/(^\s*)|(\s*$)/g, '');
};
$(function() {
  $("body").on("keyup", ".ll-numberbox", function(e) {
    if(e.which == 8 || e.which == 0 || (e.which >= 48 && e.which <= 57 && e.ctrlKey == false && e.shiftKey == false)) {
      return false;
    }
    var t_v = $(this).val().trim().replace(/[^\d\.\-]/g, '');
    $(this).val(t_v);
  })
  
  $("body").on("blur", ".ll-numberbox", function(e) {
    var options = $(this).attr("data-options").split(",");
    var t_v = $(this).val().trim().replace(/[^\d\.\-]/g, '');
    if (t_v == '') {
      $(this).val(t_v);
      return false;
    }
    
    if(t_v.startWith(".")) {
      t_v = "0" + t_v;
    }

    var a1, a2;
    var sp = t_v.split(".");
    if (sp.length >= 2) {
      a1 = sp[0];
      a2 = sp[1];
    } else {
      a1 = sp[0];
      a2 = '00';
    }
    t_v = a1 + "." + a2;

    var min, max, precision = 0;// 最小值，最大值，小数位

    for (var i = 0; i < options.length; i++) {
      if (options[i].startWith("min:"))
        min = options[i].replace("min:", "");
      if (options[i].startWith("max:"))
        max = options[i].replace("max:", "");
      if (options[i].startWith("precision:"))
        precision = parseInt(options[i].replace("precision:", ""));
    }
    if (parseFloat(t_v) - parseFloat(min) < 0) {
      t_v = min;
    }
    if (parseFloat(t_v) - parseFloat(max) > 0) {
      t_v = max;
    }

    t_v = parseFloat(t_v).toFixed(precision)
    $(this).val(t_v);
  })
})