To calculate the values of check boxes but have a Syntaxerror!

I am very new to this and from reading threads i ihave found a way to calculate a sum when checkboxes are ticked.

event.value = 0;

if(this.getField("Check Box34").value!"OFF")event.value+=11900;
if(this.getField("Check Box35").value!"OFF")event.value+=19575;

I am getting a SyntaxError: Missing ) after condition 2: at line 3

Please can you help me?