JavaScript（JS）随记

偏执的太偏执、 2022-09-09 06:44 129阅读 0赞

## 判断是否为空： ##

![watermark_type_ZHJvaWRzYW5zZmFsbGJhY2s_shadow_50_text_Q1NETiBAfueWhg_size_20_color_FFFFFF_t_70_g_se_x_16][]

## JavaScript随机获取数组Array中的值： ##

let colors = ["orange","red","blue","yellow"];
    let color = colors[Math.floor(Math.random()*colors.length)];

# js 解析出rgba字符串里的各个值 #

![watermark_type_ZHJvaWRzYW5zZmFsbGJhY2s_shadow_50_text_Q1NETiBAfueWhg_size_20_color_FFFFFF_t_70_g_se_x_16 1][]

![2021090309205774.png][]

mounted() {
        let color = "rgba(19, 206, 102, 0.8)";
    
        console.log("R this.rgbaNum(color, 0):", this.rgbaNum(color, 0));
        console.log("G this.rgbaNum(color, 1):", this.rgbaNum(color, 1));
        console.log("B this.rgbaNum(color, 2):", this.rgbaNum(color, 2));
        console.log("A this.rgbaNum(color, 3):", this.rgbaNum(color, 3));
      },
      methods: {
        rgbaNum(rgba, index) {
          return rgba.match(/(\d(\.\d+)?)+/g)[index];
        }
      }

# 改变鼠标样式 #

document.getElementById("app").style.cursor = "default";

![watermark_type_ZHJvaWRzYW5zZmFsbGJhY2s_shadow_50_text_Q1NETiBAfueWhg_size_20_color_FFFFFF_t_70_g_se_x_16 2][]

# div跟随鼠标移动 #

![20210903172450705.gif][]

<template>
      <div
        style="width: 50px; height: 50px; background-color: red; position: fixed"
        :style="{ left: left, top: top }"
      ></div>
    </template>
    
    <script>
    export default {
      data() {
        return {
          left: "",
          top: "",
        };
      },
      computed: {},
      created() {},
      mounted() {
        document.addEventListener("mousemove", (e) => {
          this.left = e.clientX + 40 + "px";
          this.top = e.clientY - 50 + "px";
        });
      },
    };
    </script>

[watermark_type_ZHJvaWRzYW5zZmFsbGJhY2s_shadow_50_text_Q1NETiBAfueWhg_size_20_color_FFFFFF_t_70_g_se_x_16]: /images/20220829/813db16f8a1d498598b708fb7bc1a491.png
[watermark_type_ZHJvaWRzYW5zZmFsbGJhY2s_shadow_50_text_Q1NETiBAfueWhg_size_20_color_FFFFFF_t_70_g_se_x_16 1]: /images/20220829/21cdf7756fed4ab1900d47b119d1f9fe.png
[2021090309205774.png]: /images/20220829/ddfe9f7a539d40468b19b8c52d9f6311.png
[watermark_type_ZHJvaWRzYW5zZmFsbGJhY2s_shadow_50_text_Q1NETiBAfueWhg_size_20_color_FFFFFF_t_70_g_se_x_16 2]: /images/20220829/fb80d78a594a474fbfd1361ef96c9dcc.png
[20210903172450705.gif]: /images/20220829/6b7d27ec7095402bbc6cb1686247e55e.png