javascript扩展函数（持续更新）

//计算字符实际长度
String.prototype.strLen = function(charset){
charset = charset || "utf8";//默认utf8编码
var length = this.length;
var realLen = 0;
for(var i = 0;i < length;i++) {
realLen += (this.charCodeAt(i) < 0 || this.charCodeAt(i) > 255) ? (charset == "utf8" ? 3 : 2) : 1;
}
return realLen;
}

//数组中搜索值
Array.prototype.indexOf= function(value, strict){
var length = this.length;
strict = strict || false;

for (var i = 0;i < length;i++) {
if (strict) {
if(value === this[i]) {
return true;
}
} else {
if (value == this[i]) {
return true;
}
}
}
return false;
}