Dynamically create variable in JavaScript function

Question

I cannot get this to work:

function formvalidation()
{
 var SiteNum= document.getElementsByName("sitesinput")[0].value; 
 var i=1;
 while (i<=SiteNum)
 {
 var SitePhone= document.getElementsByName(site['i'])[0].value; 
 alert(SitePhone);
 i++;
 }
}

If I alert like so: alert('document.getElementsByName(site["'+i+'"])[0].value'); it will display the following:

document.getElementsByName(site["1"])[0].value
document.getElementsByName(site["2"])[0].value
document.getElementsByName(site["3"])[0].value

But I cannot get it to go into a variable.

Thanks for looking, B.

Answer 1

Try replacing the line

var SitePhone= document.getElementsByName(site['i'])[0].value;

for

var SitePhone= document.getElementsByName(site[i])[0].value;

Answer 2

Remove the quotes from i. Use a for loop since it fits the use case better than a while loop.

function formvalidation()
{
 var SiteNum= document.getElementsByName("sitesinput")[0].value,
 SitePhone;
 for(var i=1; i<=SiteNum; i++)
 {
 SitePhone = document.getElementsByName(site[i])[0].value; 
 alert(SitePhone);
 }
}

Also, JavaScript does not have block-level scoping, only function-level.

I like this solution, however it wont work without the quotes (") i.e. if do everything the same, but put the name in myself, like ("site[1]") - it will work.

I see where you're headed now.

SitePhone = document.getElementsByName('site[' + i + ']')[0].value; 

• Bifterss: I like this solution, however it wont work without the quotes (") i.e. if do everything the same, but put the name in myself, like ("site[1]") - it will work. Any ideas.
• Matt Ball: Oh, so site isn't an array that contains names? See my edit.

Answer 3

You are putting quotes around the i in the line

var SiteNum = document.getElementsByName(site['i'])[0].value

which is looking for the element keyed by the string 'i' instead of the value of the variable i. Try removing the quotes.

Answer 4

Try

 alert(document.getElementsByName(site[i])[0].value);