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Example 9.1:
Creating and Checking an Array
Click on the buttons to see what is held in the specified positions in the arrays. What you see for the second to last button depends on the version of the browser you're using. In Netscape Navigator 2 you'll see 187--the array length, the number passed to the array in parentheses. In Netscape Navigator 3 and later, and in Internet Explorer 3, you'll see null, because in those browsers the [0] position in the array no longer holds the length.
This is the script we used in the HEAD:
<![CDATA[
<SCRIPT LANGUAGE="JAVASCRIPT">
<!--
function makeArray(n) {
this.length = n
for (var i=1; i <= n; i++){
this[i] = null;
}
return this
}
var acode = new makeArray(187)
var area = new makeArray(187)
area[1] = "Alabama "; acode[1] = 205
area[2] = "Alabama "; acode[2] = 334
area[3] = "Alaska "; acode[3] = 907
area[4] = "Alberta "; acode[4] = 403
area[5] = "Antigua "; acode[5] = 268
area[6] = "Arizona "; acode[6] = 520
area[7] = "Arizona "; acode[7] = 602
area[8] = "Arkansas "; acode[8] = 501
area[9] = "Bahamas "; acode[9] = 242
area[10] = "Barbados "; acode[10] = 246
area[11] = "Bermuda "; acode[11] = 441
area[12] = "British Columbia "; acode[12] = 250
area[13] = "British Columbia "; acode[13] = 604
//-->
</SCRIPT>
]]>
And this form:
<![CDATA[
<FORM>
<INPUT TYPE="BUTTON" VALUE="What's in area Position 12?" onclick="alert(area[12])"><P>
<INPUT TYPE="BUTTON" VALUE="What's in acode Position 12?" onclick="alert(acode[12])"><P>
<INPUT TYPE="BUTTON" VALUE="What's in area Position 110?" onclick="alert(area[110])"><P>
<INPUT TYPE="BUTTON" VALUE="What's in area Position 0?" onclick="alert(area[0])"><P>
<INPUT TYPE="BUTTON" VALUE="What's the area length (area.length)?" onclick="alert(area.length)"><P>
</FORM>
]]>
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