前端常用函数汇总

一、获取查询字符串字段

    function query_url(name){
        var query = location.search.substring(1),
            arry = [],
            len,
            i,
            single_query = [],
            property,
            obj = {};

        arry = query.split("&");
        len = arry.length;

        for(i = 0; i < len; i++){
            single_query = arry[i].split("=");
            property = single_query[0];
            obj[property] = single_query[1];
        }
        return obj[name];
    }

　　var name = url_query(name);


二、SMS验证码倒计时效果-------点第一次开始倒计时；倒计时未完成点击无效；倒计时完成点击出新的倒计时

var timer,
    _time = Boolean(timer);
if(_time){
    return true;
}else{
    if(sms.disabled){
        sms.removeAttribute("disabled");
    }
    var time_num = 60;
    sms_btn.innerText ="(" + time_num + ")秒再次获取";

    timer = setInterval(function(){
        time_num--;
        sms_btn.innerText ="(" + time_num + ")秒再次获取";
        if(time_num == 1){
            sms_btn.innerText ="重新获取验证码";
            clearInterval(timer);
            timer = false;
        }
    },1000);
}

三、获取带汉字的字符串的长度

function cc_len(str){
    var len=0,
        str_len = str.length,
        i,
        charcode;
    for(i = 0; i<str_len; i++){
        charcode = str.charCodeAt(i);
        if(charcode>=0 && charcode<=128){
            len++;
        }else{
            len+=2;
        }
    }
    return len;
}

四、去除DOM的指定类名函数

function drop_class(dom,str){
    var arr = [],
        class_str,
        new_class="",
        len,
        i;
    class_str = dom.className;
    arr = class_str.split(" ");
    len = arr.length;
    for(i=0; i<len; i++){
        if(arr[i] !== str){
            new_class +=(" "+arr[i]);
        }
    }
    dom.className = new_class.substr(1);
}

五、【兼容函数】取消浏览器默认行为

function stopDefault( e ) {
    if (e&&e.preventDefault ){
        e.preventDefault();
    }else{
        window.event.returnValue = false;
    }
    return false;
}