javascript - setInterval() timings are... off? -

i'm baffled this... appears overly-complex system of setinterval() lines, off tad. maybe timings trying catch up? it's little weird , i'm not sure why.

http://jsfiddle.net/dr3amtw1st/hv3fa/embedded/result/

var number=0; // not change! var key1=true, key2=false, key3=false, key4=false, key5=false; // not change! var key6=false, key7=false, key8=false, key9=false; // not change! var climbspeed=2000; // climbing speed in milliseconds. don't change unless know you're doing. var raised=100; // amount raised far. able changed. var goal=250; // goal, obviously... :p able changed.  var c1=setinterval(function(){document.getelementbyid("amount").innerhtml="$"+number++;},climbspeed); var c2, c3, c4, c5, c6, c7, c8, c9, c10;  var check=setinterval( function() {     if (number>0 && key1==true) {         key1=false;         clearinterval(c1);         climbspeed=1500;         c2=setinterval(function(){document.getelementbyid("amount").innerhtml="$"+number++;},climbspeed);         key2=true;     }     if (number>3 && key2==true) {         key2=false;         clearinterval(c2);         climbspeed=700;         c3=setinterval(function(){document.getelementbyid("amount").innerhtml="$"+number++;},climbspeed);         key3=true;     }     if (number>9 && key3==true) {         key3=false;         clearinterval(c3);         climbspeed=200;         c4=setinterval(function(){document.getelementbyid("amount").innerhtml="$"+number++;},climbspeed);         key4=true;     }     if (number>(.15*raised) && key4==true) {         key4=false;         clearinterval(c4);         climbspeed=100;         c5=setinterval(function(){document.getelementbyid("amount").innerhtml="$"+number++;},climbspeed);         key5=true;     }     if (number>(.20*raised) && key5==true) {         key5=false;         clearinterval(c5);         climbspeed=90;         c6=setinterval(function(){document.getelementbyid("amount").innerhtml="$"+number++;},climbspeed);         key6=true;     }     if (number>(.30*raised) && key6==true) {         key6=false;         clearinterval(c6);         climbspeed=110;         c7=setinterval(function(){document.getelementbyid("amount").innerhtml="$"+number++;},climbspeed);         key7=true;     }     if (number>(raised-20) && key7==true) {         key7=false;         clearinterval(c7);         climbspeed=500;         c8=setinterval(function(){document.getelementbyid("amount").innerhtml="$"+number++;},climbspeed);         key8=true;     }     if (number>(raised-11) && key8==true) {         key8=false;         clearinterval(c8);         climbspeed=650;         c9=setinterval(function(){document.getelementbyid("amount").innerhtml="$"+number++;},climbspeed);         key9=true;     }     if (number>=(raised-10) && key9==true) {         key9=false;         clearinterval(c9);         climbspeed=900;         c10=setinterval(function(){document.getelementbyid("amount").innerhtml="$"+number++;},climbspeed);     }     if (number>raised) {         clearinterval(c10);         document.getelementbyid("amount").style.color="red";         //document.getelementbyid("amount").style.fontsize="250px";     } },climbspeed);  function stop() { alert("climbspeed: " + climbspeed + "\n" + "number: " + number + "\n" + "raised: " + raised); //clearinterval(c1); //clearinterval(c2); //clearinterval(c3); //clearinterval(c4); //clearinterval(c5); //clearinterval(c6); //clearinterval(c7); //clearinterval(c8); //clearinterval(c9); //clearinterval(c10); } 

the jsfiddle above looks little off far css goes, think that's jsfiddle itself. looks fine when run 1 document in google chrome (and i've made run in google chrome). 1 time application used on own computer, once, fund raiser thermometer. pay attention number , javascript. want numbers smoother. thought using percentages (.90*raised), have pretty same effect. what's going on here timings , climbspeed? also, buttons @ top debugging purposes. won't in final draft of program.

you setting setinterval multiple times, , it's repeating every 2s. after next 2s make setinterval logic part, it's running double setinterval function. if wish change numbers in save interval, use single settimout function.