JavaScript 小代码

JavaScript 前补“0”操作 

1. [代码]传统代码   

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/**
 * 前补0操作
 * @param number String 待操作字符串
 * @param length int 目标长度
 */
function addZero(number, length) {
    var buffer = "";
    if (number ==  "") {
        for (var i = 0; i < length; i ++) {
            buffer += "0";
        }
    } else {
        if (length < number.length) {
            return "";
        } else if (length == number.length) {
            return number;
        } else {
            for (var i = 0; i < (length - number.length); i ++) {
                buffer += "0";
            }
            buffer += number;
        }
    }
    return buffer;
}

2. [代码]这个代码更简洁     

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function addZero(str,length){              
    return new Array(length - str.length + 1).join("0") + str;             
}

JavaScript 根据长度截取字符串,超长部分追加...

1. [代码]js代码

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/**
 * 根据长度截取先使用字符串,超长部分追加...
 * @param str 对象字符串
 * @param len 目标字节长度
 * @return 处理结果字符串
 */
function cutString(str, len) {
    //length属性读出来的汉字长度为1
    if(str.length*2 <= len) {
        return str;
    }
    var strlen = 0;
    var s = "";
    for(var i = 0;i < str.length; i++) {
        s = s + str.charAt(i);
        if (str.charCodeAt(i) > 128) {
            strlen = strlen + 2;
            if(strlen >= len){
                return s.substring(0,s.length-1) + "...";
            }
        } else {
            strlen = strlen + 1;
            if(strlen >= len){
                return s.substring(0,s.length-2) + "...";
            }
        }
    }
    return s;
}
原文地址:https://www.cnblogs.com/xiaohong/p/5111948.html