Subtotal array

[mouac01]

I have this array:

[{"acct":"A1","dr":100,"cr":100},{"acct":"A2","dr":200,"cr":200},
{"acct":"A1","dr":300,"cr",300},{"acct":"A2","dr":400,"cr",400}]

How would I get the subtotal of each acct so that total for A1 dr/cr
is 400 and total for A2 dr/cr is 600.
TIA...

 

[scripts.contact]

I have this array:

[{"acct":"A1","dr":100,"cr":100},{"acct":"A2","dr":200,"cr":200},
{"acct":"A1","dr":300,"cr",300},{"acct":"A2","dr":400,"cr",400}]

How would I get the subtotal of each acct so that total for A1 dr/cr
is 400 and total for A2 dr/cr is 600.

-----
function getTotal(arr,acc){
var i=0,n,drtotal=0,crtotal=0;
while(n=arr[i++])
if(n.acct==acc){
drtotal+=n.dr
crtotal+=n.cr
}
return [drtotal,crtotal]
}

-----

Example:
d=[{"acct":"A1","dr":100,"cr":100},{"acct":"A2","dr":200,"cr":200},
{"acct":"A1","dr":300,"cr":350},{"acct":"A2","dr":400,"cr":400}]
alert(getTotal(d,"A1"))

 

[mouac01]

[{"acct":"A1","dr":100,"cr":100},{"acct":"A2","dr":200,"cr":200},
{"acct":"A1","dr":300,"cr",300},{"acct":"A2","dr":400,"cr",400}]

How would I get the subtotal of each acct so that total for A1 dr/cr
is 400 and total for A2 dr/cr is 600.

-----
function getTotal(arr,acc){
var i=0,n,drtotal=0,crtotal=0;
while(n=arr[i++])
if(n.acct==acc){
drtotal+=n.dr
crtotal+=n.cr
}
return [drtotal,crtotal]
}

-----

Example:
d=[{"acct":"A1","dr":100,"cr":100},{"acct":"A2","dr":200,"cr":200},
{"acct":"A1","dr":300,"cr":350},{"acct":"A2","dr":400,"cr":400}]
alert(getTotal(d,"A1"))

Thanks for your help.
I've decided to use this:

Array.prototype.subtotal=function(grp,field1,field2){
for(var i=0,sum=0;i<this.length;i++){
if(this[field1]==grp){
sum+=Number(this[field2].toString().replace(/\$|\,/g,'')) || 0;
}
}
return sum;
}