感觉算法上有好多地方可以优化，暂放，以备忘

js 套用公用计算

<div>
  <input type="text" id="input_value" onkeydown="enterIn(event);" />
  <input type="button" value="计算" id="cal_btn" />
</div>
<div>
  结果:<span id="ret_value"></span>
</div>
<div>
  公式:<span id="ret_cal"></span>
</div>
<script>
function calcuation(value) {
   var tmp = "";
   var ret = 0;
   if(value >1000 && value<=10000) {
     ret = 0;
     tmp = "0";
   } else if(value >10000 && value <= 100000) {
     ret = (value-10000)*0.04+1000;
     tmp = "("+value+"-10000)*0.04+1000"
   } else if(value > 100000 && value <= 500000) {
     ret = (value-100000)*0.035+90000*0.04+1000;
     tmp = "("+value+"-100000)*0.035+90000*0.04+1000"
   } else if(value > 500000 && value <= 1000000) {
     ret = (value-500000)*0.03+400000*0.035+90000*0.04+1000;
     tmp = "("+value+"-500000)*0.03+400000*0.035+90000*0.04+1000;"
   } else if(value > 1000000 && value <= 5000000) {
     ret = (value-1000000)*0.025+500000*0.03+400000*0.035+90000*0.04+1000;
     tmp = "("+value+"-1000000)*0.025+500000*0.03+400000*0.035+90000*0.04+1000"
   } else if(value > 5000000 && value <= 10000000) {
     ret = (value-5000000)*0.02+4000000*0.025+500000*0.03+400000*0.035+90000*0.04+1000;
     tmp = "("+value+"-5000000)*0.02+4000000*0.025+500000*0.03+400000*0.035+90000*0.04+1000"
   } else if(value > 10000000 && value <= 50000000) {
     ret = (value-10000000)*0.0175+5000000*0.02+4000000*0.025+500000*0.03+400000*0.035+90000*0.04+1000;
     tmp = "("+value+"-10000000)*0.0175+5000000*0.02+4000000*0.025+500000*0.03+400000*0.035+90000*0.04+1000;"
   } else if (value > 50000000) {
     ret = (value - 50000000)*0.015 + 40000000*0.0175+5000000*0.02+4000000*0.025+500000*0.03+400000*0.035+90000*0.04+1000;
     tmp = "("+value+"-50000000)*0.015 + 40000000*0.0175+5000000*0.02+4000000*0.025+500000*0.03+400000*0.035+90000*0.04+1000;"
   } else {
      alert("error num:"+value);
   }
   return [parseInt(ret),tmp]
}
//监视回车
function enterIn(evt){
  var evt=evt?evt:(window.event?window.event:null);//兼容IE和FF
  if (evt.keyCode==13)
    calcuation_mm()
}

//按钮点击
document.getElementById("cal_btn").onclick = function(){ calcuation_mm(); };

//显示计算结果值
function calcuation_mm() {
    var value = parseInt(document.getElementById("input_value").value);
    var ret = calcuation(value);
    var ret_value = ret[0];
    var ret_cal = ret[1];
    document.getElementById("ret_value").innerHTML = ret_value;
    document.getElementById("ret_cal").innerHTML = ret_cal;
}
</script>