判断字符串长度

//判断字符串长度
    function strlen(str) {
        var len = 0;
        for (var i = 0; i < str.length; i++) {
            var c = str.charCodeAt(i);
            //单字节加1
            if ((c >= 0x0001 && c <= 0x007e) || (0xff60 <= c && c <= 0xff9f)) {
                len++;
            }
            else {
                len += 2;
            }
        }
        return len;
    }

 

 

 

 

//计算字符串字节数，中文算两个字节
function GetByteLength(str) {
    var len = str.length;
    var byteLen = 0;
    for (var i = 0; i < len; i++) {
        if (str.charCodeAt(i) < 27 || str.charCodeAt(i) > 126) {
            byteLen += 2;
        }
        else {
            byteLen++;
        }
    }
    return byteLen;
}

//截取字符串，中文算两个字节
function SubString(str, len, hasDot) {
    var newLength = 0;
    var newStr = "";
    var chineseRegex = /[^\x00-\xff]/g;
    var singleChar = "";
    var strLength = str.replace(chineseRegex, "**").length;
    for (var i = 0; i < strLength; i++) {
        singleChar = str.charAt(i).toString();
        if (singleChar.match(chineseRegex) != null) {
            newLength += 2;
        }
        else {
            newLength++;
        }
        if (newLength > len) {
            break;
        }
        newStr += singleChar;
    }
    if (hasDot && strLength > len) {
        newStr += "..";
    }
    return newStr;