I want to test whether a JavaScript variable has a value.
var splitarr = mystring.split( );
aparam = splitarr [0]
anotherparam = splitarr [1]
//.... etc
However the string might not have enough entries so later I want to test it.
if ( anotherparm /* contains a value */ )
How do I do this?
In general it's sort of a gray area... what do you mean by has a value? The values null and undefined are legitimate values you can assign to a variable...
The String function split() always returns an array so use the length property of the result to figure out which indices are present. Indices out of range will have the value undefined.
But technically (outside the context of String.split()) you could do this:
js>z = ['a','b','c',undefined,null,1,2,3]
a,b,c,,,1,2,3
js>typeof z[3]
undefined
js>z[3] === undefined
true
js>z[3] === null
false
js>typeof z[4]
object
js>z[4] === undefined
false
js>z[4] === null
true
