Underligt javascript spørgmsål

Kode 

<form name="searchArt">
<select name="artCategory" size="4" onChange="updateSelectSearchArt(this.options[this.options.selectedIndex].value)" style="width: 150px">
<option value="0">Vælg kategori</option>
<option value="1">Maleri</option>
<option value="5">Skulptur</option>
</select>

<select name="artType" size="4" style="width: 150px" onClick="alert(this.options[this.options.selectedIndex].value)">
</select>
</form>

<script type="javascript/text">
var artTypeList=document.searchArt.artType

var artType=new Array()
artType[0]=["Vælg kategori|0"]
artType[1]=["ikke relevant|0", "test|test"]
artType[5]=["ikke relevant|0", "Test1|Test1", "Test2|Test2"]
artType[11]=["ikke relevant|0", "Test3|Test3", "Test4|Test4"]

function updateSelectSearchArt(artCategorySelected){
artTypeList.options.length=0
  for (i=0; i<artType[artCategorySelected].length; i++)
    artTypeList.options[artTypeList.options.length]=new Option(artType[artCategorySelected][i].split("|")[0], artType[artCategorySelected][i].split("|")[1])
}
</script>