Question

如何为每个空字段将字符串值传递给警报消息？

我有w，t，a，c和s。例如，如果w为空，则应该给出警告信息“必须填写必填字段”。同样的为他人而战。

我的javascript：

function addvalidation(){
        var w = document.forms["shop"]["w"].value;
        var t = document.forms["shop"]["t"].value;
        var a = document.forms["shop"]["a"].value;
        var c = document.forms["shop"]["c"].value;
        var s = document.forms["shop"]["s"].value;
        var c = document.forms["shop"]["c"].value;

        if (w == "" || t =="" || a == ""|| c == "" || s == "" || c == "") {
                alert("Mandatory fields must be filled out");
                return false;
            }

Answer 1

您可以过滤document.forms["shop"][e].value==""的位置并加入它们以便在警告中显示

注意/更新：您需要加入密钥而不是值

e = Object.keys(document.forms["shop"]).filter(function(e){
            return document.forms["shop"][e].value==""
        });


   errors = e.join(" ");
   alert(errors +" are mandatory");

工作演示：

＆＃13;

        document.forms["shop"] =[] ;

        document.forms["shop"]["w"] = {};
        document.forms["shop"]["t"]={};
        document.forms["shop"]["a"] ={};
        document.forms["shop"]["c"]= {};

        
        document.forms["shop"]["w"].value = "";
        document.forms["shop"]["t"].value="abc";
        document.forms["shop"]["a"].value = "";
         document.forms["shop"]["c"].value="abcd";
        

    e = Object.keys(document.forms["shop"]).filter(function(e){
        return document.forms["shop"][e].value==""
    });
   
   
   errors = e.join(" ");
   alert(errors +" are mandatory");

＆＃13;

Answer 2

您可以尝试类似

的内容

＆＃13;

function addvalidation() {
  var form = document.forms["workshop"];
  var ef = ['w', 't', 'a', 'c', 's'].filter(function(f) {
    return !form[f].value
  })

  if (ef.length) {
    alert("Mandatory fields " + ef.join() + " must be filled out");
    return false;
  }
}

＆＃13;

<form name="workshop" onsubmit="return addvalidation()">
  <input name="w" />
  <input name="t" />
  <input name="a" />
  <input name="c" />
  <input name="s" />
  <input type="submit" />
</form>

＆＃13;

Answer 3

尝试使用此特定字段警报，

function addvalidation() {
   var form = document.forms["workshop"];
   var field="";
   var ef = ['w', 't', 'a', 'c', 's'].filter(function(f) {
     if(form[f].value=="" && field==""){
        field=f; 
     }
   })

  if (field!="") {
    alert("Mandatory field " + field + " must be filled out");
    return false;
  }
}

如何将字符串值传递给javascript警报

3 个答案: