纯javascript验证邮箱格式

gistfile1.js

//邮箱验证纯javascript
function checkEmail(emailStr){
    var start=0;
    var end=emailStr.length;
    while(start<end){//判断是否含有除"@"和"."之外的特殊字符和中文字符
            var charcode=emailStr.charCodeAt(start);
            if(!(charcode==45||charcode==46||
                (charcode>=48&charcode<=59)||
                (charcode>=64&charcode<=90)||                (charcode>=97&charcode<=122))){
                //alert("有非法字符"+emailStr.charAt(start));
                return false;
            }
            start++;
    }   
                  
    var emailStrArr=emailStr.split("@");
    if(emailStrArr.length!=2){//判断@的个数是否为有且仅有一个
        return false;
    }else if(emailStrArr[0]==''||emailStrArr[1]==''){//判断"@"的位置是否正确
        return false;
    }else{
        if(emailStrArr[0].split(".").length>1){//判断@前面的字符串是否含有"."
            return false;
        }
        var emailStr2Arr=emailStrArr[1].split(".");
        if(emailStr2Arr.length<2){//判断@后面的字符串是否含有"."
            return false;
        }else if(emailStr2Arr[0]==''||emailStr2Arr[emailStr2Arr.length]==''){//判断"."的位置是否正确
            return false;
        }else if(!(emailStr2Arr[emailStr2Arr.length-1]=='com'||
                 emailStr2Arr[emailStr2Arr.length-1]=='cn'||
                 emailStr2Arr[emailStr2Arr.length-1]=='gov'||
                 emailStr2Arr[emailStr2Arr.length-1]=='edu'||
                 emailStr2Arr[emailStr2Arr.length-1]=='net'||
                 emailStr2Arr[emailStr2Arr.length-1]=='org'||
                 emailStr2Arr[emailStr2Arr.length-1]=='int'||
                 emailStr2Arr[emailStr2Arr.length-1]=='mil')){//判断域名后缀名是否正确
            return false;
        }
    }
    return true;
}
alert(checkEmail("asddd@gui.com"));