Almighty converter & Useful functions

# TextArea

v=t1.value t2.value=v p1.innerHTML=v // 註解 Comment v2=t3.value t4.value=v2 p2.innerHTML=v2

My ID is p1

My ID is p2

*=already preloaded on this page

# 小工具 Utilities

• *Object keys listing: objls( object_to_list_properties )
  function objls(obj) { let objO=obj; let listK={}; while(obj!=null) { Object.getOwnPropertyNames(obj).forEach(i=>{ listK[i]=1; }); obj=obj.__proto__; } let ret=Object.keys(listK); let oname=objO.constructor.name; if(oname=="Number") ret.unshift(objO); else if(oname=="String") ret.unshift(objO.substr(0,1000)); else if(oname=="Array") ret.unshift(objO.slice(0,10).join(",")); ret.unshift(objO.constructor.name); return ret; }

• *Copy to clipboard: cbcopy( "text_to_copy" )
  function cbcopy(s){ obj=document.createElement("textarea"); obj.value=(s+""); document.body.append(obj); obj.select(); document.execCommand("copy"); obj.remove(); }
• Download current page html
  Type `javascript:` at url and paste
  (()=>{s=document.documentElement.outerHTML;a=document.createElement("a");a.href="data:text/html,"+encodeURIComponent(s);a.download="webpage.html";a.click();})()
• Eruda Console: Paste as URL
  Type `javascript:` at url and paste
  (function () { var script = document.createElement('script'); script.src="https://cdn.jsdelivr.net/npm/eruda"; document.body.appendChild(script); script.onload = function () { eruda.init() } })()
• *jQuery
  (function () { var script = document.createElement('script'); script.src="https://code.jquery.com/jquery-3.4.1.min.js"; script.integrity="sha256-CSXorXvZcTkaix6Yvo6HppcZGetbYMGWSFlBw8HfCJo="; script.crossOrigin="anonymous"; document.body.appendChild(script); })()
• *Advanced alert and showlist:
  function alert2(pgText,cvtBR,asText){ if(pgText && typeof(pgText)=="object") {pgText=JSON.stringify(pgText,null,1); cvtBR=true;} pgText+=""; if(cvtBR && !asText) pgText=pgText.split("\n").join("<br>"); var dlg=$(`<div>`) .css("position","fixed") .css("width","80vw") .css("height","80vh") .css("left","10vw") .css("top","5vh") .css("background-color","#38383c") .css("color","white") .css("overflow-wrap","break-word") .css("border-radius","20px") .css("font-size","20px") .css("padding","10px") .css("overflow","auto") .attr("onclick","$(this).remove()"); if(asText) dlg[0].innerText=(pgText); else dlg.html(pgText); $("body").append(dlg); } async function showlist(title,list,multi){ if(typeof(list)=="string") { list=list.split(","); } if(!list) return ""; return (await new Promise(resolve=>{ showlist_resolve=resolve; alert2(`<h3 class="alert alert-success text-center"> ${title}</h3> \n`+ `<ul class="list-group">\n`+ ` <li class="list-group-item list-group-item-danger text-center">取消Cancel</li> `+ list.map(i=>(` <li class="list-group-item list-group-item-info" onclick="showlist_resolve(this.innerHTML);">${i}</li> `)).join("\n")+ `</ul> `); })); //new Promise }

# 數學 Mathematics

• 排列Permutations: patt( array_of_items )
  function patt(arr){ if(arr.constructor.name!="Array") return []; arr=arr.slice(); if(arr.length==1) return [arr]; else if(arr.length==2) return [arr,arr.slice().reverse()]; else { let sum=[]; let el=arr.shift(); let darr=patt(arr); for(var i in new Array(arr.length+1).fill(0)) sum.push(...darr.map(item=> { let cp=item.slice(); cp.splice(i,0,el); return cp; })); return sum; } }
• 組合Combinations: comb( array_of_items , number_of_selection )
  function comb(a,n){ var ids=new Array(n).fill(0).map((i,ind)=>ind); var res=[]; //console.log(indexes); var evs=""; for(i in ids) evs+=`for(ids[${i}]=((ids[${i}-1]==null)?(-1):ids[${i}-1])+1;ids[${i}]<=a.length-n+${i};ids[${i}]++){\n`; evs+=`res.push(a.filter( (ii,ind)=>(ids.indexOf(ind)!=-1) ));\n`; evs+="}\n".repeat(n); console.log(evs); eval(evs); return (res); }