JavaScript Comparison and Logical Operators
Ref:http://www.w3schools.com/js/js_comparisons.asp
1 var r = 1; 2 var result = r || 2; 3 console.log(result); 4 //output: 1 5 6 r = 0; 7 result = r || 2; 8 console.log(result); 9 //output: 2 10 11 r = 0; 12 result = r || "string"; 13 console.log(result); 14 //output: string