数据库字段+1的问题(js实现)

function doAdd(a,b) {var str = "";var lenA = parseInt(a.length);var lenB = parseInt(b.length);var maxLen ="";if(lenA > lenB){maxLen=parseInt(lenA)}else{maxLen=parseInt(lenB)}var minLen =""; if(lenA < lenB){  minLen=parseInt(lenA)} else{minLen=parseInt(lenB)}var strTmp = "";for (var i = maxLen - minLen; i > 0; i--) {strTmp += "0";}// 把长度调整到相同if (maxLen == lenA) {b = strTmp + b;} elsea = strTmp + a;var JW = 0;// 进位for (var i = maxLen - 1; i >= 0; i--) {var tempA = parseInt(a.charAt(i));var tempB = parseInt(b.charAt(i));var temp;if (tempA + tempB + JW >= 10 && i != 0) {temp = parseInt(tempA + tempB + JW - 10);JW = 1;} else {temp = parseInt(tempA + tempB + JW);JW = 0;}str = temp + str;}return str;}假如数据库字段是：000000009doAdd（"000000009","1"）结果是：000000010