Posts Tagged urldecode

URL encode / decode in JavaScript

Decoding and Encoding URLs in JavaScript should be a pretty easy thing to do especially since all browsers still have the functionality built-in. Interestingly no browser allows the JavaScript runtime to use this feature. So I had to write it for myself.
The code I came up with is far from perfect but it worked for me. To decode an URL use url_decode(url) and to reverse it just call the utf16to8 function. The rest does your browser for you.

function url_decode(str){
var hex = /^[0-9a-fA-F]{2}/;
var out='';
var arr = str.split('%');
if(arr.length<2) return str;
for(var i=0;i= 0x0001) && (c <= 0x007F)) {
	    out += str.charAt(i);
	} else if (c > 0x07FF) {
	    out += String.fromCharCode(0xE0 | ((c >> 12) & 0x0F));
	    out += String.fromCharCode(0x80 | ((c >>  6) & 0x3F));
	    out += String.fromCharCode(0x80 | ((c >>  0) & 0x3F));
	} else {
	    out += String.fromCharCode(0xC0 | ((c >>  6) & 0x1F));
	    out += String.fromCharCode(0x80 | ((c >>  0) & 0x3F));
	}
    }
    return out;
}

function utf8to16(str) {
    var out, i, len, c;
    var char2, char3;

    out = "";
    len = str.length;
    i = 0;
    while(i < len) {
	c = str.charCodeAt(i++);
	switch(c >> 4)
	{ 
	  case 0: case 1: case 2: case 3: case 4: case 5: case 6: case 7:
	    // 0xxxxxxx
	    out += str.charAt(i-1);
	    break;
	  case 12: case 13:
	    // 110x xxxx   10xx xxxx
	    char2 = str.charCodeAt(i++);
	    out += String.fromCharCode(((c & 0x1F) << 6) | (char2 & 0x3F));
	    break;
	  case 14:
	    // 1110 xxxx  10xx xxxx  10xx xxxx
	    char2 = str.charCodeAt(i++);
	    char3 = str.charCodeAt(i++);
	    out += String.fromCharCode(((c & 0x0F) << 12) |
					   ((char2 & 0x3F) << 6) |
					   ((char3 & 0x3F) << 0));
	    break;
	}
    }
    return out;
}

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