var BASE64={ enKey: 'ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/', deKey: new Array( -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, 62, -1, -1, -1, 63, 52, 53, 54, 55, 56, 57, 58, 59, 60, 61, -1, -1, -1, -1, -1, -1, -1, 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, -1, -1, -1, -1, -1, -1, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, -1, -1, -1, -1, -1 ), encode: function(src){ //用一个数组来存放编码后的字符,效率比用字符串相加高很多。 var str=new Array(); var ch1, ch2, ch3; //src=escape(src); var pos=0; //每三个字符进行编码。 while(pos+3<=src.length){ ch1=src.charCodeAt(pos++); ch2=src.charCodeAt(pos++); ch3=src.charCodeAt(pos++); str.push(this.enKey.charAt(ch1>>2), this.enKey.charAt(((ch1<<4)+(ch2>>4))&0x3f)); str.push(this.enKey.charAt(((ch2<<2)+(ch3>>6))&0x3f), this.enKey.charAt(ch3&0x3f)); } //给剩下的字符进行编码。 if(pos<src.length){ ch1=src.charCodeAt(pos++); str.push(this.enKey.charAt(ch1>>2)); if(pos<src.length){ ch2=src.charCodeAt(pos); str.push(this.enKey.charAt(((ch1<<4)+(ch2>>4))&0x3f)); str.push(this.enKey.charAt(ch2<<2&0x3f), '='); }else{ str.push(this.enKey.charAt(ch1<<4&0x3f), '=='); } } //组合各编码后的字符,连成一个字符串。 return str.join(''); }, decode: function(src){ //用一个数组来存放解码后的字符。 var str=new Array(); var ch1, ch2, ch3, ch4; var pos=0; //过滤非法字符,并去掉'='。 src=src.replace(/[^A-Za-z0-9\+\/]/g, ''); //decode the source string in partition of per four characters. while(pos+4<=src.length){ ch1=this.deKey[src.charCodeAt(pos++)]; ch2=this.deKey[src.charCodeAt(pos++)]; ch3=this.deKey[src.charCodeAt(pos++)]; ch4=this.deKey[src.charCodeAt(pos++)]; str.push(String.fromCharCode( (ch1<<2&0xff)+(ch2>>4), (ch2<<4&0xff)+(ch3>>2), (ch3<<6&0xff)+ch4)); } //给剩下的字符进行解码。 if(pos+1<src.length){ ch1=this.deKey[src.charCodeAt(pos++)]; ch2=this.deKey[src.charCodeAt(pos++)]; if(pos<src.length){ ch3=this.deKey[src.charCodeAt(pos)]; str.push(String.fromCharCode((ch1<<2&0xff)+(ch2>>4), (ch2<<4&0xff)+(ch3>>2))); }else{ str.push(String.fromCharCode((ch1<<2&0xff)+(ch2>>4))); } } //组合各解码后的字符,连成一个字符串。 //return unescape(str.join('')); return str.join(''); } }; //调用时使用escape和unescape函数对字符串转码即可支持中文(unicode) var code = BASE64.encode('hellow world!'); alert(code+" "+BASE64.decode(code));
Javascript base64编解码
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转载自cisumer.iteye.com/blog/2306916
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