Javascript function

1.下载convas中的图片 👍

var convas = document.getElementById("canvas");

var dataURL = convas.toDataURL();

var link = document.createElement('a');

link.href=dataURL;

link.download='image.png';

document.body.appendChild(link);

link.click();

2.下载svg中的图片 👍

svg无法当成图片打开，可以使用工具转换成你想要的图片格式

var svg =document.getElementById("aaa")

var svgData=new XMLSerializer().serializeToString(svg);

var blob=new Blob([svgData],{type:"image/svg+xml;charset=utf-8"});

var url=URL.createObjectURL(blob);

var a=document.createElement("a");

a.href=url;

a.download="image.svg";

a.click();

写入cookie

//name=>key value=>cookie值 daysToExpire=>失效时间 传空则默认浏览器关闭就失效
function setCookie(name, value, daysToExpire) {
    var expirationDate = '';
    if (daysToExpire) {
        var expirationTime = new Date();
        expirationTime.setTime(expirationTime.getTime() + (daysToExpire * 24 * 60 * 60 * 1000));
        expirationDate = "; expires=" + expirationTime.toUTCString();
    }

    document.cookie = name + "=" + value + expirationDate + "; path=/";
}

读取cookie

//读取cookie
function getCookie(name) {
    var cookieName = name + "=";
    var cookiesArray = document.cookie.split(';');
    for (var i = 0; i < cookiesArray.length; i++) {
        var cookie = cookiesArray[i].trim();
        if (cookie.indexOf(cookieName) === 0) {
            return cookie.substring(cookieName.length, cookie.length);
        }
    }
    return null;
}

转换成字符串

//举例:
//var boolValue = true;
//console.log(String(boolValue) === "true");
function boolToString(val){
   return String(val);
}

获取checkbox是否选中

//ele => $(".chkbox");
//获取checkbox选中属性
function getChkboxIsSelect(ele){
  ele.prop("checked");// true / false
}

使用父级页面的function时,判断funciton是否存在

//父级方法存在,则调用
function fatherfunctionIsExist(){
  //funcName 为你要使用的父级function
  if (window.parent && typeof window.parent.funcName === 'function') {
      window.parent.funcName();
  }
}

获取url中的参数

    //返回值是object {a:"我是a",b:"我是b"}
    function getUrlParameters() {
        var urlParams = {};
        var match,
            regex = /([^&=]+)=([^&]*)/g;
        var searchString = window.location.search.substring(1);
        while ((match = regex.exec(searchString))) {
            var key = decodeURIComponent(match[1]);
            var value = decodeURIComponent(match[2]);
            urlParams[key] = value;
        }
        return urlParams;
    }