var numReg = /^-?[0-9]+.?[0-9]*$/

Array.prototype.min = function() {
  return this.reduce(function(preValue, curValue,index,array) {
   if ( numReg.test(preValue) && numReg.test(curValue) ) {
      return preValue > curValue ? curValue : preValue;
   } else if ( numReg.test(preValue) ) {
   return preValue;
   } else if ( numReg.test(curValue) ) {
   return curValue;
   } else {
   return 0;
   }
  })
}

Array.prototype.max = function() {
  return this.reduce(function(preValue, curValue,index,array) {
   if ( numReg.test(preValue) && numReg.test(curValue) ) {
      return preValue < curValue ? curValue : preValue;
   } else if ( numReg.test(preValue) ) {
   return preValue;
   } else if ( numReg.test(curValue) ) {
   return curValue;
   } else {
   return 0;
   }
  })
}

function getMaximin (arr,maximin) { 
 if (maximin == "max") { 
  return Math.max.apply(Math, arr); 
 }else if (maximin == "min") { 
  return Math.min.apply(Math, arr); 
 } 
} 
 
var a = [3,2,4,2,10] 
 
var b = [12,4,45,786,9,78] 
 
alert("aMax:" + getMaximin(a,"max") + "---aMin:" + getMaximin(a,"min") + "---bMax:" + getMaximin(b,"max") + "---bMin:" + getMaximin(b,"min"))//aMax:10---aMin:2---bMax:786---bMin:4 
 
function getMaximin (arr,maximin) {
 if (maximin == "max") {
  return Math.max.apply(Math, arr);
 }else if (maximin == "min") {
  return Math.min.apply(Math, arr);
 }
}
 
var a = [3,2,4,2,10]
 
var b = [12,4,45,786,9,78]
 
alert("aMax:" + getMaximin(a,"max") + "---aMin:" + getMaximin(a,"min") + "---bMax:" + getMaximin(b,"max") + "---bMin:" + getMaximin(b,"min"))//aMax:10---aMin:2---bMax:786---bMin:4

//最小值
Array.prototype.min = function() {
var min = this[0];
var len = this.length;
for (var i = 1; i < len; i++){ 
if (this[i] < min){ 
min = this[i]; 
} 
} 
return min;
}
//最大值
Array.prototype.max = function() { 
var max = this[0];
var len = this.length; 
for (var i = 1; i < len; i++){ 
if (this[i] > max) { 
max = this[i]; 
} 
} 
return max;
}

if (typeof Array.prototype['max'] == 'undefined') { 
Array.prototype.max = function() { 
... ...
}
}

Array.max = function( array ){ 
return Math.max.apply( Math, array );
};

Array.min = function( array ){ 
return Math.min.apply( Math, array );
};

Array.prototype.max = function(){ 
return Math.max.apply({},this) 
} 
Array.prototype.min = function(){ 
return Math.min.apply({},this) 
} 
[1,2,3].max()// => 3 
[1,2,3].min()// => 1