檢測頁面是否發生變化
vue+elementUI項目中，遇到一個技術問題，就是在一個修改頁面中，點擊返回按鈕的時候，需要檢測當前頁面是否發生變化。（當用戶在頁面修改字段的時候，不小心點到返回按鈕，這個時候應該要給個提示，是否確認返回，這是一個很合理的需求）
修改的頁面字段太多一個個比較太麻煩。所以最後我用MD5過濾成一個串碼，比較前後兩次串碼是否發生變化來判斷頁面是否發生變化。
如何運用MD5進行轉換：
- 首先將頁面上需要檢測變化的字段一個個連起來串成一個大的字符串
- 將大的字符串傳進MD5的方法中。例如：
var str1 = "12345";
var str1md5 = md5(str1);
str1md5便是一個串碼。
當你進入修改頁面的時候，得到初始化的串碼。當你點擊返回的時候，得到當前頁面最新的串碼。就可以檢測頁面是否發生變化。
當頁面上有的地方的數據是一個數組的時候，你還會遇到一個問題：
就是你初始化的數組和你改變數據後得到的數組是一樣的，這是由於vue項目數據雙向綁定的緣故。你無法得到之前初始化的數組，此時，你便需要做一個深拷貝。
我試過網上很多方法，只有通過JSON.stringify成功了。例如：
this.oldrowData = JSON.stringify(this.rowData)//初始化時獲取數組
this.newrowData =JSON.stringify(this.rowData)//數組發生變化得到的新數組
通過比較oldrowData和newrowData可以檢測數組是否發生變化。
MD5的js文件（網上有很多，直接運用到項目中即可）：
export function md5(string) {
function md5_RotateLeft(lValue, iShiftBits) {
return (lValue << iShiftBits) | (lValue >>> (32 - iShiftBits));
}
function md5_AddUnsigned(lX, lY) {
var lX4, lY4, lX8, lY8, lResult;
lX8 = (lX & 0x80000000);
lY8 = (lY & 0x80000000);
lX4 = (lX & 0x40000000);
lY4 = (lY & 0x40000000);
lResult = (lX & 0x3FFFFFFF) + (lY & 0x3FFFFFFF);
if (lX4 & lY4) {
return (lResult ^ 0x80000000 ^ lX8 ^ lY8);
}
if (lX4 | lY4) {
if (lResult & 0x40000000) {
return (lResult ^ 0xC0000000 ^ lX8 ^ lY8);
} else {
return (lResult ^ 0x40000000 ^ lX8 ^ lY8);
}
} else {
return (lResult ^ lX8 ^ lY8);
}
}
function md5_F(x, y, z) {
return (x & y) | ((~x) & z);
}
function md5_G(x, y, z) {
return (x & z) | (y & (~z));
}
function md5_H(x, y, z) {
return (x ^ y ^ z);
}
function md5_I(x, y, z) {
return (y ^ (x | (~z)));
}
function md5_FF(a, b, c, d, x, s, ac) {
a = md5_AddUnsigned(a, md5_AddUnsigned(md5_AddUnsigned(md5_F(b, c, d), x), ac));
return md5_AddUnsigned(md5_RotateLeft(a, s), b);
};
function md5_GG(a, b, c, d, x, s, ac) {
a = md5_AddUnsigned(a, md5_AddUnsigned(md5_AddUnsigned(md5_G(b, c, d), x), ac));
return md5_AddUnsigned(md5_RotateLeft(a, s), b);
};
function md5_HH(a, b, c, d, x, s, ac) {
a = md5_AddUnsigned(a, md5_AddUnsigned(md5_AddUnsigned(md5_H(b, c, d), x), ac));
return md5_AddUnsigned(md5_RotateLeft(a, s), b);
};
function md5_II(a, b, c, d, x, s, ac) {
a = md5_AddUnsigned(a, md5_AddUnsigned(md5_AddUnsigned(md5_I(b, c, d), x), ac));
return md5_AddUnsigned(md5_RotateLeft(a, s), b);
};
function md5_ConvertToWordArray(string) {
var lWordCount;
var lMessageLength = string.length;
var lNumberOfWords_temp1 = lMessageLength + 8;
var lNumberOfWords_temp2 = (lNumberOfWords_temp1 - (lNumberOfWords_temp1 % 64)) / 64;
var lNumberOfWords = (lNumberOfWords_temp2 + 1) * 16;
var lWordArray = Array(lNumberOfWords - 1);
var lBytePosition = 0;
var lByteCount = 0;
while (lByteCount < lMessageLength) {
lWordCount = (lByteCount - (lByteCount % 4)) / 4;
lBytePosition = (lByteCount % 4) * 8;
lWordArray[lWordCount] = (lWordArray[lWordCount] | (string.charCodeAt(lByteCount) << lBytePosition));
lByteCount++;
}
lWordCount = (lByteCount - (lByteCount % 4)) / 4;
lBytePosition = (lByteCount % 4) * 8;
lWordArray[lWordCount] = lWordArray[lWordCount] | (0x80 << lBytePosition);
lWordArray[lNumberOfWords - 2] = lMessageLength << 3;
lWordArray[lNumberOfWords - 1] = lMessageLength >>> 29;
return lWordArray;
};
function md5_WordToHex(lValue) {
var WordToHexValue = "",
WordToHexValue_temp = "",
lByte, lCount;
for (lCount = 0; lCount <= 3; lCount++) {
lByte = (lValue >>> (lCount * 8)) & 255;
WordToHexValue_temp = "0" + lByte.toString(16);
WordToHexValue = WordToHexValue + WordToHexValue_temp.substr(WordToHexValue_temp.length - 2, 2);
}
return WordToHexValue;
};
function md5_Utf8Encode(string) {
string = string.replace(/\r\n/g, "\n");
var utftext = "";
for (var n = 0; n < string.length; n++) {
var c = string.charCodeAt(n);
if (c < 128) {
utftext += String.fromCharCode(c);
} else if ((c > 127) && (c < 2048)) {
utftext += String.fromCharCode((c >> 6) | 192);
utftext += String.fromCharCode((c & 63) | 128);
} else {
utftext += String.fromCharCode((c >> 12) | 224);
utftext += String.fromCharCode(((c >> 6) & 63) | 128);
utftext += String.fromCharCode((c & 63) | 128);
}
}
return utftext;
};
var x = Array();
var k, AA, BB, CC, DD, a, b, c, d;
var S11 = 7,
S12 = 12,
S13 = 17,
S14 = 22;
var S21 = 5,
S22 = 9,
S23 = 14,
S24 = 20;
var S31 = 4,
S32 = 11,
S33 = 16,
S34 = 23;
var S41 = 6,
S42 = 10,
S43 = 15,
S44 = 21;
string = md5_Utf8Encode(string);
x = md5_ConvertToWordArray(string);
a = 0x67452301;
b = 0xEFCDAB89;
c = 0x98BADCFE;
d = 0x10325476;
for (k = 0; k < x.length; k += 16) {
AA = a;
BB = b;
CC = c;
DD = d;
a = md5_FF(a, b, c, d, x[k + 0], S11, 0xD76AA478);
d = md5_FF(d, a, b, c, x[k + 1], S12, 0xE8C7B756);
c = md5_FF(c, d, a, b, x[k + 2], S13, 0x242070DB);
b = md5_FF(b, c, d, a, x[k + 3], S14, 0xC1BDCEEE);
a = md5_FF(a, b, c, d, x[k + 4], S11, 0xF57C0FAF);
d = md5_FF(d, a, b, c, x[k + 5], S12, 0x4787C62A);
c = md5_FF(c, d, a, b, x[k + 6], S13, 0xA8304613);
b = md5_FF(b, c, d, a, x[k + 7], S14, 0xFD469501);
a = md5_FF(a, b, c, d, x[k + 8], S11, 0x698098D8);
d = md5_FF(d, a, b, c, x[k + 9], S12, 0x8B44F7AF);
c = md5_FF(c, d, a, b, x[k + 10], S13, 0xFFFF5BB1);
b = md5_FF(b, c, d, a, x[k + 11], S14, 0x895CD7BE);
a = md5_FF(a, b, c, d, x[k + 12], S11, 0x6B901122);
d = md5_FF(d, a, b, c, x[k + 13], S12, 0xFD987193);
c = md5_FF(c, d, a, b, x[k + 14], S13, 0xA679438E);
b = md5_FF(b, c, d, a, x[k + 15], S14, 0x49B40821);
a = md5_GG(a, b, c, d, x[k + 1], S21, 0xF61E2562);
d = md5_GG(d, a, b, c, x[k + 6], S22, 0xC040B340);
c = md5_GG(c, d, a, b, x[k + 11], S23, 0x265E5A51);
b = md5_GG(b, c, d, a, x[k + 0], S24, 0xE9B6C7AA);
a = md5_GG(a, b, c, d, x[k + 5], S21, 0xD62F105D);
d = md5_GG(d, a, b, c, x[k + 10], S22, 0x2441453);
c = md5_GG(c, d, a, b, x[k + 15], S23, 0xD8A1E681);
b = md5_GG(b, c, d, a, x[k + 4], S24, 0xE7D3FBC8);
a = md5_GG(a, b, c, d, x[k + 9], S21, 0x21E1CDE6);
d = md5_GG(d, a, b, c, x[k + 14], S22, 0xC33707D6);
c = md5_GG(c, d, a, b, x[k + 3], S23, 0xF4D50D87);
b = md5_GG(b, c, d, a, x[k + 8], S24, 0x455A14ED);
a = md5_GG(a, b, c, d, x[k + 13], S21, 0xA9E3E905);
d = md5_GG(d, a, b, c, x[k + 2], S22, 0xFCEFA3F8);
c = md5_GG(c, d, a, b, x[k + 7], S23, 0x676F02D9);
b = md5_GG(b, c, d, a, x[k + 12], S24, 0x8D2A4C8A);
a = md5_HH(a, b, c, d, x[k + 5], S31, 0xFFFA3942);
d = md5_HH(d, a, b, c, x[k + 8], S32, 0x8771F681);
c = md5_HH(c, d, a, b, x[k + 11], S33, 0x6D9D6122);
b = md5_HH(b, c, d, a, x[k + 14], S34, 0xFDE5380C);
a = md5_HH(a, b, c, d, x[k + 1], S31, 0xA4BEEA44);
d = md5_HH(d, a, b, c, x[k + 4], S32, 0x4BDECFA9);
c = md5_HH(c, d, a, b, x[k + 7], S33, 0xF6BB4B60);
b = md5_HH(b, c, d, a, x[k + 10], S34, 0xBEBFBC70);
a = md5_HH(a, b, c, d, x[k + 13], S31, 0x289B7EC6);
d = md5_HH(d, a, b, c, x[k + 0], S32, 0xEAA127FA);
c = md5_HH(c, d, a, b, x[k + 3], S33, 0xD4EF3085);
b = md5_HH(b, c, d, a, x[k + 6], S34, 0x4881D05);
a = md5_HH(a, b, c, d, x[k + 9], S31, 0xD9D4D039);
d = md5_HH(d, a, b, c, x[k + 12], S32, 0xE6DB99E5);
c = md5_HH(c, d, a, b, x[k + 15], S33, 0x1FA27CF8);
b = md5_HH(b, c, d, a, x[k + 2], S34, 0xC4AC5665);
a = md5_II(a, b, c, d, x[k + 0], S41, 0xF4292244);
d = md5_II(d, a, b, c, x[k + 7], S42, 0x432AFF97);
c = md5_II(c, d, a, b, x[k + 14], S43, 0xAB9423A7);
b = md5_II(b, c, d, a, x[k + 5], S44, 0xFC93A039);
a = md5_II(a, b, c, d, x[k + 12], S41, 0x655B59C3);
d = md5_II(d, a, b, c, x[k + 3], S42, 0x8F0CCC92);
c = md5_II(c, d, a, b, x[k + 10], S43, 0xFFEFF47D);
b = md5_II(b, c, d, a, x[k + 1], S44, 0x85845DD1);
a = md5_II(a, b, c, d, x[k + 8], S41, 0x6FA87E4F);
d = md5_II(d, a, b, c, x[k + 15], S42, 0xFE2CE6E0);
c = md5_II(c, d, a, b, x[k + 6], S43, 0xA3014314);
b = md5_II(b, c, d, a, x[k + 13], S44, 0x4E0811A1);
a = md5_II(a, b, c, d, x[k + 4], S41, 0xF7537E82);
d = md5_II(d, a, b, c, x[k + 11], S42, 0xBD3AF235);
c = md5_II(c, d, a, b, x[k + 2], S43, 0x2AD7D2BB);
b = md5_II(b, c, d, a, x[k + 9], S44, 0xEB86D391);
a = md5_AddUnsigned(a, AA);
b = md5_AddUnsigned(b, BB);
c = md5_AddUnsigned(c, CC);
d = md5_AddUnsigned(d, DD);
}
return (md5_WordToHex(a) + md5_WordToHex(b) + md5_WordToHex(c) + md5_WordToHex(d)).toLowerCase();
}
檢測頁面是否發生變化