分享javascript常用的小功能代码片段

作者：管理员

发布时间：2013/6/19 20:15:27

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转载请自觉注明原文：http://www.jq-school.com/Show.aspx?id=286

//去左空格;
function ltrim(s) {
    return s.replace(/^\s*/, "");
}


//去右空格;
function rtrim(s) {
    return s.replace(/\s*$/, "");
}


//左右空格;
function trim(s) {
    return rtrim(ltrim(s));
}


//替换
function replace(s, t, u) {
    i = s.indexOf(t);
    r = "";
    if (i == -1) return s;
    r += s.substring(0, i) + u;
    if (i + t.length < s.length) r += replace(s.substring(i + t.length, s.length), t, u);
    return r;
}


//检查非法字符
//str 要检查的字符
//badwords 非法字符 &|<>=
function checkbadwords(str, badwords) {
    if (typeof(str) != "string" || typeof(badwords) != "string") {
        return (false);
    }
    for (i = 0; i < badwords.length; i++) {
        bad = badwords.charAt(i);
        for (j = 0; j < str.length; j++) {
            if (bad == str.charAt(j)) {
                return false;
                break;
            }
        }
    }
    return true;
}


//检查合法字符,限制只能输入的字符
//str 要检查的字符
//goodwords 合法字符 1234567890abcdefghijklmnopqrstuvwxyz
function checkgoodwords(str, goodwords) {
    if (typeof(str) != "string" || typeof(goodwords) != "string") {
        return (false);
    }
    for (i = 0; i < str.length; i++) {
        this_str = str.charAt(i);
        for (j = 0; j < goodwords.length; j++) {
            if (this_str == goodwords.charAt(j)) {
                break;
            }
            if (j == goodwords.length - 1) {
                return false;
            }
        }
    }
    return true;
}


//函 数 名：chkinteger
//功能介绍：检查是否为数字
//参数说明：要检查的字符串
//返 回 值：false:不是 true:是
function chkinteger(checkStr) {
    var checkOK = "0123456789+-";
    var allValid = true;
    for (i = 0; i < checkStr.length; i++) {
        ch = checkStr.charAt(i);
        if (checkOK.indexOf(ch) == -1) {
            allValid = false;
            break;
        }
        if ((ch == '+' || ch == '-') && i > 0) {
            allValid = false;
            break;
        }
    }
    return (allValid);
}


//函 数 名：chklength
//功能介绍：检查字符串的长度
//参数说明：要检查的字符串
//返 回 值：字节长度值
function chklength(checkStr) {
    var n = 0;
    for (i = 0; i < checkStr.length; i++) {
        chcode = checkStr.charCodeAt(i);
        if (chcode >= 0 && chcode <= 255) {
            n++;
        } else {
            n += 2;
        }
    }
    return (n);
}


//复选框全选和不全选
//使用方法：
//<input name="chkAll" type="checkbox" id="chkAll" onclick=CheckAll(this.form) value="checkbox">
function unselectall() {
    if (document.myform.chkAll.checked) {
        document.myform.chkAll.checked = document.myform.chkAll.checked & 0;
    }
}
function CheckAll(form) {
    for (var i = 0; i < form.elements.length; i++) {
        var e = form.elements[i];
        if (e.Name != "chkAll" && e.disabled == false) e.checked = form.chkAll.checked;
    }
}


//check date
//return: 1,days 2,false
//2005-12-19 2005-12-29
function checkdate(start_date, end_date) {
    //alert("start_date:["+start_date+"] end_date:["+end_date+"]");
    //isnull
    if (start_date == "" || end_date == "") {
        //alert("false");
        return false;
    }
    var strSeparator = "-"; //split symbol
    //is-
    if (start_date.charAt(4) != strSeparator && start_date.charAt(7) != strSeparator && end_date.charAt(4) != strSeparator && end_date.charAt(7) != strSeparator) {
        //alert(start_date.charAt(7));
        return false;
    }
    var strDateArrayStart;
    var strDateArrayEnd;
    strDateArrayStart = start_date.split(strSeparator);
    strDateArrayEnd = end_date.split(strSeparator);
    var strDateS = new Date(strDateArrayStart[0] + "/" + strDateArrayStart[1] + "/" + strDateArrayStart[2]);
    var strDateE = new Date(strDateArrayEnd[0] + "/" + strDateArrayEnd[1] + "/" + strDateArrayEnd[2]);
    //check date
    var intDay;
    intDay = (strDateE - strDateS) / (1000 * 3600 * 24);
    //alert(intDay);
    return intDay;
}


//checkdate_month
//return: 1,true 2,false
//2005-12-19 2005-12-29
//month: number
function checkdate_month(start_date, end_date, month) {
    //alert("start_date:["+start_date+"] end_date:["+end_date+"]");
    //isnull
    if (start_date == "" || end_date == "" || month == "") {
        //alert("false");
        return false;
    }
    var strSeparator = "-"; //split symbol
    //is-
    if (start_date.charAt(4) != strSeparator && start_date.charAt(7) != strSeparator && end_date.charAt(4) != strSeparator && end_date.charAt(7) != strSeparator) {
        //alert(start_date.charAt(7));
        return false;
    }
    var strDateArrayStart;
    var strDateArrayEnd;
    strDateArrayStart = start_date.split(strSeparator);
    strDateArrayEnd = end_date.split(strSeparator);
    var strDateS = new Date(strDateArrayStart[0] + "/" + strDateArrayStart[1] + "/" + strDateArrayStart[2]);
    var strDateE = new Date(strDateArrayEnd[0] + "/" + strDateArrayEnd[1] + "/" + strDateArrayEnd[2]);
    //check date
    var intDay;
    intDay = (strDateE - strDateS) / (1000 * 3600 * 24);
    //alert(intDay);
    var intMonth = intDay / 30;
    if (intMonth > month) {
        return false;
    }
    return true;
}