js的常用函数

1. 获取元素坐标

var getPos:function(o){//取元素坐标
    var x = 0, y = 0;
    do{
        x += o.offsetLeft;
        y += o.offsetTop;
    }while(o=o.offsetParent);
    return {'x':x,'y':y};
}

2. 获取当前script文件的路径

var strJsPath='';
(function(){
    try {
        throw Error("获取路径")
    }catch(ex){
        if(ex.fileName)//Firefox
            strJsPath=ex.fileName
        else if(ex.stack)//Chrome
            strJsPath=(ex.stack.match(/at\s+(.*?):\d+:\d+/)||['',''])[1];
        else if(ex.sourceURL)//Safari
            strJsPath=ex.sourceURL 
    }
    if(strJsPath)return; //其实所有浏览器都可以用下面的
    var scripts=document.getElementsByTagName("script"),script=scripts[scripts.length-1];
    strJsPath=document.querySelector?script.src:script.getAttribute("src",4)//IE8直接.src
})()
alert(strJsPath);

3. 获取当前script中的参数

var getScriptArgs=function(){//获取多个参数
    var scripts=document.getElementsByTagName("script"),
    script=scripts[scripts.length-1],//因为当前dom加载时后面的script标签还未加载，所以最后一个就是当前的script
    src=script.src,
    reg=/(?:\?|&)(.*?)=(.*?)(?=&|$)/g,
    temp,res={};
    while((temp=reg.exec(src))!=null) res[temp[1]]=decodeURIComponent(temp[2]);
    return res;
};
var args=getScriptArgs();
alert(args.a+" | "+args.b+" | "+args.c);
//假如上面的js是在这个js1.js的脚本中< script type="text/javascript" src="js1.js?a=abc&b=汉字&c=123">< /script>

var getScriptArg=function(key){//获取单个参数
    var scripts=document.getElementsByTagName("script"),
    script=scripts[scripts.length-1],
    src=script.src;
    return (src.match(new RegExp("(?:\\?|&)"+key+"=(.*?)(?=&|$)"))||['',null])[1];
};
alert(getScriptArg("c"));

4.控制上传file的文件类型

<input type="file" onchange="checkExt(this)"/>

<script type="text/javascript"> 
var checkExt=function(file) {
    if(!(/(?:jpg|gif)$/i.test(file.value))) {
        alert("只允许上传jpg和gif的图片");
        if(window.ActiveXObject) {//for IE
            file.select();//select the file ,and clear selection
            document.selection.clear();
        } else if(window.opera) {//for opera
            file.type="text";file.type="file";
        } else file.value="";//for FF,Chrome,Safari
    } else {
        alert("ok");//or you can do nothing here.
    }
};
</script>

5.js获取url中的参数

//lastest:
var getArgs=function() {//get url querystring
    var params=document.location.search,reg=/(?:^\?|&)(.*?)=(.*?)(?=&|$)/g,temp,args={};
    while((temp=reg.exec(params))!=null) args[temp[1]]=decodeURIComponent(temp[2]);
    return args;
};
//只取一个：
var queryString=function(key){
    return (document.location.search.match(new RegExp("(?:^\\?|&)"+key+"=(.*?)(?=&|$)"))||['',null])[1];
}
var args=getArgs();
alert(args.name+" | "+args.sex+" | "+args.age);
//测试链接：< a href="?name=abc&sex=男&age=12">test getQueryString

//deprecated
var getArgs=function() {
    var params=document.location.search.substr(1),reg=/(?:^|&)(.*?)=(.*?)(?:&|$)/g,temp,args={};
    while((temp=reg.exec(params))!=null) {        
        args[temp[1]]=temp[2];
        reg.lastIndex-=1;//减1，下一次从结束的&开始匹配
    }
    return args;
};
var getArgs=function(){
    var sarg = document.location.search.substr(1),rv={};
    rv.filename = document.location.pathname.replace(/.*\//ig,'');
    if(!sarg){return rv;}
    var aarg = sarg.split('&'),atmp=[];
    for(var i=0;i< aarg.length;i++){
        atmp = aarg[i].split('=');
        rv[atmp[0]] = unescape(atmp[1]);
    }
    return rv;
};

 6.js Unicode编码转换

/*
 *js Unicode编码转换
 */ 
var decToHex = function(str) {
    var res=[];
    for(var i=0;i < str.length;i++)
        res[i]=("00"+str.charCodeAt(i).toString(16)).slice(-4);
    return "\\u"+res.join("\\u");
}
var decToHex2 = function(str) {
    var res="",c;
    for(var i=0;i < str.length;i++){
        c=str.charCodeAt(i);
        res+=(c< 32 || c==38 || c>127)?"\\u"+c.toString(16):str.charAt(i)
    }
    return res
}
var hexToDec = function(str) {
    str=str.replace(/\\/g,"%");
    return unescape(str);
}
var str=decToHex2("decToHex unicode 编码转换");
alert("编码后："+str+"\n\n解码后："+hexToDec(str));

7.js HTML编码转换

/*
 *js HTML Encode
 */ 
var htmlEncode=function(str) {//HTML des encode.
    var res=[];
    for(var i=0;i < str.length;i++)
        res[i]=str.charCodeAt(i);
    return "&#"+res.join(";&#")+";";
};
var htmlEncode2=function(s) {
    var r = "", c;
    for (var i = 0; i < s.length; i++) {
        c = s.charCodeAt(i);
        r += (c < 32 || c == 38 || c > 127) ? ("&#" + c + ";") : s.charAt(i);
    }
    return r;
};
//s.replace(/([\u4e00-\u9fa5]+)/g,function($,$1) {
//    return htmlEncode($1);
//})
var htmlHexEncode=function(str) {//HTML hex encode.
    var res=[];
    for(var i=0;i < str.length;i++)
        res[i]=str.charCodeAt(i).toString(16);
    return "&#"+String.fromCharCode(0x78)+res.join(";&#"+String.fromCharCode(0x78))+";";//x ，防止ff下&#x 转义
};
var htmlDecode = function(str) {
    return str.replace(/&#(x)?([^&]{1,5});?/g,function($,$1,$2) {
        return String.fromCharCode(parseInt($2 , $1 ? 16:10));
    });
};
var s="htmlEncode HTML 编码转换 &#";
var s1=htmlEncode(s)+"\n\n只对双字节和&编码："+htmlEncode2(s);
var s2=htmlDecode(s1);
alert("编码前："+s+"\n\n编码后："+s1+"\n\n解码后："+s2);

var s="htmlHexEncode HTML 编码转换&#";
var s1=htmlHexEncode(s);
var s2=htmlDecode(s1);
alert("编码前："+s+"\n\n编码后："+s1+"\n\n解码后："+s2);

8. js 全半角转换

/*
 *全角空格为12288，半角空格为32
 *其他字符半角(33-126)与全角(65281-65374)的对应关系是：均相差65248
 */
function SBC(text) {
    return text.replace(/[\x20-\x7e]/g, function($) {
        return $ == " " ? "\u3000" : String.fromCharCode($.charCodeAt(0) + 0xfee0);
    });
}
var toDBC=function(input) {//to DBC case
    var res="",c;
    for(var i=0;i< input.length;i++) {
        c=input.charCodeAt(i);
        if(c >=0xFF01 && c <=0xFF5E)// 65281 65374
            res+=String.fromCharCode(c-0xFEE0);//65248
        else if(c==0x3000)//12288
            res+=String.fromCharCode(0x20);//32
        else
            res+=input.charAt(i);
    }
    return res;
}
var toSBC=function(input) {//to SBC case
    var res="",c;
    for(var i=0; i < input.length;i++) {
        c=input.charCodeAt(i);
        if(c>=0x21 && c<=0x7e)//33 126
            res+=String.fromCharCode(c+0xFEE0);
        else if(c==0x20)
            res += String.fromCharCode(0x3000);
        else
            res += input.charAt(i);
    }
    return res;
}
var s="，哦哦，hello　ｓｓｓｓ！＃～";
var s1=toDBC(s);
var s2=toSBC(s1);
alert("原字符："+s+"\n\ntoDBC："+s1+"\n\ntoSBC："+s2);