for(var i=0;i<=100;i+=2){ //i+=2 意思为i=i+2 num +=i // } document.write("偶数和:"+num+"") 1. 2. 3. 4. 5. 3.总和 var num1=0 for(var i=0;i<=100;i+=1){ num1+=i } 1. 2. 3. 4. 4.大马驮2石粮食,中马驮1石粮食,两头小马驮一石粮食,要用100匹马,驮100...