Javascript语句符合所有条件可能出了什么问题

Question

这段代码符合所有条件，请有人告诉我我要去哪里哪里； 我已经检查过，但是我看不到代码有任何问题。 为什么所有条件都得到满足。

<script>
$( document ).ready(function() {
    var style = $('#el_teams_TeamFormation span').html(); 
    alert (style);
         if (style = "4-4-2")
          { 
            document.getElementById('footballpitch1').style.display = "none";
            document.getElementById('footballpitch2').style.display = "none";
            document.getElementById('footballpitch3').style.display = "none";
            document.getElementById('footballpitch4').style.display = "none";
            document.getElementById('footballpitch1').style.display = "block";
         }
         if (style = "3-4-3")
          {
            document.getElementById('footballpitch1').style.display = "none";
            document.getElementById('footballpitch2').style.display = "none";
            document.getElementById('footballpitch3').style.display = "none";
            document.getElementById('footballpitch4').style.display = "none";
            document.getElementById('footballpitch2').style.display = "block";
         } 
         if (style = "3-5-2") {
            document.getElementById('footballpitch1').style.display = "none";
            document.getElementById('footballpitch2').style.display = "none";
            document.getElementById('footballpitch3').style.display = "none";
            document.getElementById('footballpitch4').style.display = "none";
            document.getElementById('footballpitch3').style.display = "block";
         }
         if (style = "4-5-1") {
            document.getElementById('footballpitch1').style.display = "none";
            document.getElementById('footballpitch2').style.display = "none";
            document.getElementById('footballpitch3').style.display = "none";
            document.getElementById('footballpitch4').style.display = "none";
            document.getElementById('footballpitch4').style.display = "block";
         }
});

Answer 1

值得熟悉各种比较运算符：

https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Operators/Comparison_Operators

简而言之，单（ = ），双（ == ）和三（ === ）等于符号对JavaScript的意义不同。

单个=是赋值运算符，因此在每个if语句中，您实际上是在要求脚本为变量style赋值“ 4-4-2”（依此类推），而不是比较这两个值。

如果使用== （强制类型）或=== （无强制），则代码应该可以正常工作。

Answer 2

if (style == "4-4-2")
          { 
            document.getElementById('footballpitch1').style.display = "none";
            document.getElementById('footballpitch2').style.display = "none";
            document.getElementById('footballpitch3').style.display = "none";
            document.getElementById('footballpitch4').style.display = "none";
            document.getElementById('footballpitch1').style.display = "block";
         }
         if (style == "3-4-3")
          {
            document.getElementById('footballpitch1').style.display = "none";
            document.getElementById('footballpitch2').style.display = "none";
            document.getElementById('footballpitch3').style.display = "none";
            document.getElementById('footballpitch4').style.display = "none";
            document.getElementById('footballpitch2').style.display = "block";
         } 
         if (style == "3-5-2") {
            document.getElementById('footballpitch1').style.display = "none";
            document.getElementById('footballpitch2').style.display = "none";
            document.getElementById('footballpitch3').style.display = "none";
            document.getElementById('footballpitch4').style.display = "none";
            document.getElementById('footballpitch3').style.display = "block";
         }
         if (style == "4-5-1") {
            document.getElementById('footballpitch1').style.display = "none";
            document.getElementById('footballpitch2').style.display = "none";
            document.getElementById('footballpitch3').style.display = "none";
            document.getElementById('footballpitch4').style.display = "none";
            document.getElementById('footballpitch4').style.display = "block";
         }