I found the script below on Google that makes sure the visitor enters a zip code that matches the state they enter. I can't get it to work for some reason and I was wondering if anybody can point out any errors. It looks like the myzip in the third function should be zip correct?

Code:
<script language="JavaScript" type="text/javascript">
<!--
	// Expects a 5-digit zip code. Prevents user from entering 5 identical digits, as in 44444.

	function checkZipDigitsIdentical(zip){
	  sample=zip.substring(0,1)
	  for(i=1;i<zip.length;i++){
	    if ((zip.substring(i,i+1))!=sample){
		  return
		}
	  }
	  error=1
	  msg=zip+" is not an acceptable zip code."
	}

	// Expects digits only, and checks that they aren't sequential, i.e. 23456 or 65432

	function checkZipDigitsSequential(zip){
	  first=zip.substring(0,1)
	  second=zip.substring(1,2)
	  diff=parseInt(first)-parseInt(second)
	  if(Math.abs(diff)!=1) return
	  if (diff == -1){  //ascending order
	    for(i=0; i<zip.length-1; i++){
	      if ((parseInt(zip.substring(i,i+1)))!=(parseInt(zip.substring(i+1,i+2))-1)) return
	    }
	  }
	  if (diff == 1){   //descending order
	    for(i=0;i<zip.length-1;i++){
	      if ((parseInt(zip.substring(i,i+1)))!=(parseInt(zip.substring(i+1,i+2))+1)) return
	    }
	  }
	  error=1
	  msg=zip+" is not an acceptable zip code."
	}
	
	// Check to make sure the zip code matches the state.
	
	function checkIllegalZip(myzip,state) {
	  var ZipAA = "340";
	  var ZipAE = "090,091,092,093,094,095,096,097,098";
	  var ZipAK = "995,996,997,998,999";
	  var ZipAL = "350,351,352,353,354,355,356,357,358,359,360,361,362,363,364,365,366,367,368,369,393";
	  var ZipAP = "962,963,964,965,966,968";
	  var ZipAR = "381,716,717,718,719,720,721,722,723,724,725,726,727,728,729,755";
	  var ZipAS = "967";
	  var ZipAZ = "850,851,852,853,854,855,856,857,858,859,860,861,862,863,864,865,873,879,880";
	  var ZipCA = "895,900,901,902,903,904,905,906,907,908,910,911,912,913,914,915,916,917,918,918,920,921,922,923,924,925,926,927,928,929,930,931,932,933,934,935,936,937,938,940,941,942,943,944,945,946,947,948,949,950,951,952,953,954,955,956,957,958,959,960,961,962,963,964,965,966";
	  var ZipCO = "800,801,802,803,805,806,807,808,809,810,811,812,813,814,815,816";
	  var ZipCT = "060,061,062,063,064,065,066,067,068,069";
	  var ZipDC = "200,201,202,203,204,205";
	  var ZipDE = "197,198,199,216,218";
	  var ZipFL = "315,320,321,322,323,324,325,326,327,328,329,330,331,332,333,334,335,336,337,338,339,340,341,342,343,344,345,346,347,348,349";
	  var ZipGA = "298,299,300,301,302,303,304,305,306,307,308,309,310,311,312,313,314,315,316,317,318,319,374,399";
	  var ZipHI = "967,968,969";
	  var ZipIA = "500,501,502,503,504,505,506,507,508,509,510,511,512,513,514,515,516,517,518,519,520,521,522,523,524,525,526,527,528,612,681";
	  var ZipID = "832,833,834,835,836,837,838,970,990";
	  var ZipIL = "527,528,600,601,602,603,604,605,606,607,608,609,610,611,612,613,614,615,616,617,618,619,620,621,622,623,624,625,626,627,628,629,631,634,635";
	  var ZipIN = "400,420,423,424,460,461,462,463,464,465,466,467,468,469,470,471,472,473,474,475,476,477,478,479";
	  var ZipKS = "641,660,661,662,663,664,665,666,667,668,669,670,671,672,673,674,675,676,678,679,739";
	  var ZipKY = "400,401,402,403,404,405,406,407,408,409,410,411,412,413,414,415,416,417,418,419,420,421,422,423,424,425,426,427,452,471,476";
	  var ZipLA = "700,701,702,703,704,705,706,707,708,709,710,711,712,713,714,717";
	  var ZipMA = "010,011,012,013,014,015,016,017,018,019,020,021,022,023,024,025,026,027,055";
	  var ZipMD = "203,206,207,208,209,210,211,212,213,214,215,216,217,218,219,267";
	  var ZipME = "038,039,040,041,042,043,044,045,046,047,048,049";
	  var ZipMI = "480,481,482,483,484,485,486,487,488,489,490,491,492,493,494,495,496,497,498,499";
	  var ZipMN = "550,551,552,553,554,555,556,557,558,559,560,561,562,563,564,565,566,567,540,581";
	  var ZipMO = "621,622,623,624,625,626,627,628,629,630,631,632,633,634,635,637,638,639,640,641,642,643,644,645,646,647,648,649,650,651,652,653,654,655,656,657,658";
	  var ZipMS = "369,381,386,387,388,389,390,391,392,393,394,395,396,397";
	  var ZipMT = "590,591,592,593,594,595,596,597,598,599,821";
	  var ZipNC = "270,271,272,273,274,275,276,277,278,279,280,281,282,283,284,285,286,287,288,289,297";
	  var ZipND = "565,557,580,581,582,583,584,585,586,587,588";
	  var ZipNE = "515,516,680,681,682,683,684,685,686,687,688,689,690,691,692,693";
	  var ZipNH = "030,031,032,033,034,035,036,036,037,038,039,050";
	  var ZipNJ = "070,071,072,073,074,075,076,077,078,079,080,081,082,083,084,085,086,087,088,089";
	  var ZipNM = "865,870,871,872,873,874,875,876,877,878,879,880,881,882,883,884";
	  var ZipNV = "889,890,891,892,893,894,895,896,897,898,961";
	  var ZipNY = "003,004,005,090,091,092,093,094,095,096,097,098,099,100,101,102,103,104,105,106,107,108,109,110,111,112,113,114,115,116,117,118,119,120,121,122,123,124,125,126,127,128,129,130,131,132,133,134,135,136,137,138,139,140,141,142,143,144,145,146,147,148,149";
	  var ZipOH = "410,430,431,432,433,435,436,437,438,439,440,441,442,443,444,445,446,447,448,449,450,451,452,453,454,455,456,457,458,459,470";
	  var ZipOK = "730,731,732,733,734,735,736,737,738,739,740,741,742,743,744,745,746,748,749,679";
	  var ZipOR = "836,970,971,972,973,974,975,976,977,978,979,986";
	  var ZipPA = "150,151,152,153,154,155,156,157,158,159,160,161,162,163,164,165,166,167,168,169,170,171,172,173,174,175,176,177,178,179,180,181,182,183,184,185,186,187,188,189,190,191,192,193,194,195,196,213,260";
	  var ZipPR = "006,007,008,009";
	  var ZipRI = "027,028,029";
	  var ZipSC = "282,290,291,292,293,294,295,296,297,298,299,309,314";
	  var ZipSD = "570,571,572,573,574,575,576,577";
	  var ZipTN = "307,370,371,372,373,374,375,376,377,378,379,380,381,382,383,384,385,386,723";
	  var ZipTX = "718,733,750,751,752,753,754,755,756,757,758,759,760,761,762,763,764,765,766,767,768,769,770,771,772,773,774,775,776,777,778,779,780,781,782,783,784,785,786,787,788,789,790,791,792,793,794,795,796,797,798,799,885";
	  var ZipUT = "840,841,842,843,844,845,846,847,893,898";
	  var ZipVA = "201,220,221,222,223,224,225,226,227,228,229,230,231,232,233,234,235,236,237,238,239,240,241,242,243,244,245,246";
	  var ZipVI = "008";
	  var ZipVT = "050,051,052,053,054,055,056,057,058,059,035,036,037";
	  var ZipWA = "835,838,972,980,981,982,983,984,985,986,987,988,989,990,991,992,993,994";
	  var ZipWI = "498,499,530,531,532,533,534,535,536,537,538,539,540,541,542,543,544,545,546,547,548,549,551";
	  var ZipWV = "246,247,248,249,250,251,252,253,254,255,256,257,258,259,260,261,262,263,264,265,266,267,268";
	  var ZipWY = "591,820,821,823,824,825,826,827,828,829,830,831";
	  var zip3 = myzip.value.substring(0,3)
	  if( eval("Zip" + state.value.toUpperCase()).indexOf(zip3,0) == -1 ) {
	    error = 1
		msg = "'" + myzip.value + "' is not a valid zip code for state " + state.value.toUpperCase() + "."
	  }
	}

//-->
</script>
<form action="" name="test" onSubmit="checkZipDigitsSequential(zip)">
<input type="text" name="state">
<br>
<input type="text" name="zip">
<br>
<input type="submit" value="Go">
</form>

Any help would be greatly appreciate.


Thanks,

John