验证输入字段
嗨,我想验证表单中的输入字段'putime',因为即使'putime'输入框为空,结果也会被计算出来,而且夜间附加费也会添加到成本中.因此,我想在'putime'为空时验证它.
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- function TaxiFare() {
- // calculates taxi fare based upon miles travelled
- // and the hour of the day in military time (0-23).
- var baseFare = 14;
- var costPerMile = 7.00;
- var nightSurcharge = 20.50; // 9pm to 6am, every night //its flat 20.50 and not per mile
- var milesTravelled = Number(document.getElementById("miles").value) || 0;
- if ((milesTravelled < 1) || (milesTravelled > 200)) {
- alert ("You must enter 1 - 200 miles");
- document.getElementById("miles").focus();
- return false;
- }
- var pickupTime = Number(document.getElementById("putime").value) || 0;
- if ((pickupTime < 0) || (pickupTime > 23) || (pickupTime==null)) { // note the hours are 0-23. There is no 24 hour, midnight is 0 hours
- alert ("The time must be 0-23 hours");
- document.getElementById("putime").focus();
- return false;
- }
- var cost = baseFare + (costPerMile * milesTravelled);
- // add the nightSurcharge to the cost if it is after
- // 8pm or before 6am
- if (pickupTime >= 21 || pickupTime < 6) {
- cost += nightSurcharge;
- }
- document.getElementById("result").innerHTML = "Your taxi fare is: $. " + cost.toFixed(2);
- }
这是表格
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- <form>
- Miles for Journey <input type="text" id = "miles" required><br>
- Pickup Time <input type = text id = "putime" required><br><br>
- <input type="button" value="Calculate Fare" onclick="TaxiFare()">
- <input type="reset" value="Clear"><br><br>
- <span id = "result"></span>
- </form>