Of Stack

javascript common function (1)

  • 2020-09-28 08:42:18
  • OfStack

Main contents list:

1, adjust the size of the picture, not out of shape (FF IE compatible)/cut the picture (overflow:hidden)
2. Control the number of characters in textarea
3. Click to display the new window
4. The input box automatically grows with the content
5. Add favorites
6. Set the home page
7. Jquery + Ajax determines whether the user exists
8. Judge whether email format is correct
9. Comprehensively judge user name (length, English field, etc.)
10. News rolling
11. Only positive integers (used by shopping cart) or positive Numbers (positive integers and positive decimals) are allowed.
12. Convert strings to Numbers
13. Determine the file format (get the file suffix)
14. Intercept the string
15. Split the string

Main Contents:
1, adjust the size of the picture, not out of shape (FF IE compatible) 


//  usage  <img src="this_image_path.jpg" onload="DrawImage(this,450,450);" /> 
 function DrawImage(ImgD,FitWidth,FitHeight){ 
 var image=new Image(); 
 image.src=ImgD.src; 
 if(image.width>0 && image.height>0){ 
  if(image.width/image.height>= FitWidth/FitHeight){ 
  if(image.width>FitWidth){ 
   ImgD.width=FitWidth; 
   ImgD.height=(image.height*FitWidth)/image.width; 
  }else{ 
   ImgD.width=image.width; 
   ImgD.height=image.height; 
  } 
  } else{ 
  if(image.height>FitHeight){ 
   ImgD.height=FitHeight; 
   ImgD.width=(image.width*FitHeight)/image.height; 
  }else{ 
   ImgD.width=image.width; 
   ImgD.height=image.height; 
  } 
  } 
 } 
 }

Shear through overflow: hidden: 


function clipImage(o, w, h){ 
 var img = new Image(); 
 img.src = o.src; 
 if(img.width >0 && img.height>0) 
 { 
 if(img.width/img.height >= w/h) 
 { 
  if(img.width > w) 
  {  
  o.width = (img.width*h)/img.height; 
  o.height = h; 
  //o.setAttribute("style", "marginLeft:-" + ((o.width-w)/2).toString() + "px"); 
  $(o).css("margin-left", "-"+((o.width-w)/2).toString() + "px"); 
  } 
  else 
  { 
  o.width = img.width; 
  o.height = img.height; 
  }  
 } 
 else 
 { 
  if(img.height > h) 
  { 
  o.height = (img.height*w)/img.width; 
  o.width = w; 
  //o.setAttribute("style", "margin-top:-" + ((o.height-h)/2).toString() + "px"); 
  //$(o).css("style", "margin-top:-" + ((o.height-h)/2).toString() + "px"); 
  $(o).css("margin-top", "-"+((o.height-h)/2).toString() + "px"); 
 } 
  else 
  { 
  o.width = img.width; 
  o.height = img.height; 
  }  
 } 
 } 
}

Example: 


<style type="text/css"> 
 ul{list-style:none;} 
 ul li{float:left;padding:1px;border:#ccc 1px solid;width:120px;height:120px;overflow:hidden;text-align:center;over-flow:hidden;} 
</style> 
<ul> 
 <li><img src="1.jpg" onload="DrawImage(this,120,120);" /></li> 
 <li><img src="2.jpg" onload="clipImage(this,120,120);" /></li> 
</ul>

2. Control the number of characters in textarea 


<script> 
/** 
 * Calculate how many characters remain in a textarea (jQuery) 
 * @param string textarea 
 * @param int maxLength 
 * @param string div 
 */ 
function charsRemain(textarea, maxLength, div) { 
 var currentLength = $(textarea).val().length; 
 
 var charsLeft = maxLength - currentLength; 
 if (charsLeft < 0) { charsLeft = 0; } 
 
 $("#"+ div +"_charsRemain").html(charsLeft); 
 
 if (currentLength > maxLength) { 
 var fullText = $(textarea).val().substring(0, maxLength); 
 $(textarea).val(fullText); 
 } 
} 
 
/** 
 * Calculate how many characters remain in a textarea (javascript) 
 * @param string textarea 
 * @param int maxLength 
 * @param string div 
 */ 
function charsRemain(textarea, maxLength, div) { 
 var currentLength = textarea.value.length; 
 
 var charsLeft = maxLength - currentLength; 
 if (charsLeft < 0) { charsLeft = 0; } 
 
 document.getElementById(div +"_charsRemain").innerHTML = charsLeft; 
 
 if (currentLength > maxLength) { 
 var fullText = textarea.value.substring(0, maxLength); 
 textarea.value = fullText; 
 } 
} 
</script> 
 
<textarea rows="5" cols="15" onkeyup="charsRemain(this, 250, 'textarea');"></textarea> 
 
<span id="textarea_charsRemain">250</span> characters remaining

3. Click to display the new window 


// Popup window  
function g_OpenWindow(pageURL, innerWidth, innerHeight) 
{ 
 var ScreenWidth = screen.availWidth 
 var ScreenHeight = screen.availHeight 
 var StartX = (ScreenWidth - innerWidth) / 2 
 var StartY = (ScreenHeight - innerHeight) / 2 
 var wins = window.open(pageURL, 'OpenWin', 'left='+ StartX + ', top='+ StartY + ', Width=' + innerWidth +', height=' + innerHeight + ', resizable=yes, scrollbars=yes, status=no, toolbar=no, menubar=no, location=no') 
 wins.focus(); 
}

Java code: 


<script language="JavaScript"> 
 //  Automatic pop-up window  
 var whatsNew = open('','_blank','top=50,left=50,width=200,height=300,' + 'menubar=no,toolbar=no,directories=no,location=no,' + 'status=no,resizable=no,scrollbars=yes'); 
 whatsNew.document.write('<center><b>news</b>< /center>'); 
 whatsNew.document.write('<p>this is a test'); 
 whatsNew.document.write('<p>deos address'); 
 whatsNew.document.write('<p align="right">' + '<a href="javascript:self.close()">Close</a>'); 
 whatsNew.document.close(); 
</script>

Unfortunately, many browsers block pop-ups and you need to manually allow them to be seen! Here is the forced pop-up window. The idea is to create an form and open it with post. 


<script language="javascript"> 
 function ForceWindow (){ 
 this.r = document.documentElement; 
 this.f = document.createElement("FORM"); 
 this.f.target = "_blank"; 
 this.f.method = "post"; 
 this.r.insertBefore(this.f, this.r.childNodes[0]); //XML DOM : insertBefore()  Method can be inserted before an existing child node 1 A new child node.  insertBefore(newchild,refchild) 
 } 
 
 ForceWindow.prototype.pop = function (sUrl){ 
 this.f.action = sUrl; 
 this.f.submit(); 
 } 
 
 window.force = new ForceWindow(); 
</script> 
 
<body onLoad="window.force.pop('http://deographics.com/')"> 
 <div> 
this is a test ! we will open the deographics's website~~ 
 </div> 
</body>

Of course there are better ways 


<script> 
 function openWin(){ 
 window.showModalDialog(url,window, "help:no;scroll:no;resizable:no;status:0;dialogWidth:420px;dialogHeight:200px;center:yes"); 
 } 
</script>

4. The input box automatically grows with the content 


// input auto length 
 // <input name="words" size="2" maxlength="100" onkeyup="checkLength(this)"/><span id="char">0</span> 
 
 function checkLength(which) { 
 var maxchar=100; 
 //var oTextCount = document.getElementById("char"); 
 iCount = which.value.replace(/[^\u0000-\u00ff]/g,"aa").length; 
 if(iCount<=maxchar){ 
  //oTextCount.innerHTML = "<font color=#FF0000>"+ iCount+"</font>"; 
  which.style.border = '1px dotted #FF0000'; 
  which.size=iCount+2; 
 }else{ 
  alert('Please input letter less than '+ maxchar); 
 } 
 }

5. Add favorites 


// addfavorite 
 function addfavorite(){ 
 if (document.all){ 
  window.external.addFavorite('http://deographics.com/','deographics'); 
 }else if (window.sidebar){ 
  window.sidebar.addPanel('deographics', 'http://deographics.com/', ""); 
 } 
 }

6. Set the home page 


function clipImage(o, w, h){ 
 var img = new Image(); 
 img.src = o.src; 
 if(img.width >0 && img.height>0) 
 { 
 if(img.width/img.height >= w/h) 
 { 
  if(img.width > w) 
  {  
  o.width = (img.width*h)/img.height; 
  o.height = h; 
  //o.setAttribute("style", "marginLeft:-" + ((o.width-w)/2).toString() + "px"); 
  $(o).css("margin-left", "-"+((o.width-w)/2).toString() + "px"); 
  } 
  else 
  { 
  o.width = img.width; 
  o.height = img.height; 
  }  
 } 
 else 
 { 
  if(img.height > h) 
  { 
  o.height = (img.height*w)/img.width; 
  o.width = w; 
  //o.setAttribute("style", "margin-top:-" + ((o.height-h)/2).toString() + "px"); 
  //$(o).css("style", "margin-top:-" + ((o.height-h)/2).toString() + "px"); 
  $(o).css("margin-top", "-"+((o.height-h)/2).toString() + "px"); 
 } 
  else 
  { 
  o.width = img.width; 
  o.height = img.height; 
  }  
 } 
 } 
}
0

7. Jquery + Ajax determine whether the user exists 


function clipImage(o, w, h){ 
 var img = new Image(); 
 img.src = o.src; 
 if(img.width >0 && img.height>0) 
 { 
 if(img.width/img.height >= w/h) 
 { 
  if(img.width > w) 
  {  
  o.width = (img.width*h)/img.height; 
  o.height = h; 
  //o.setAttribute("style", "marginLeft:-" + ((o.width-w)/2).toString() + "px"); 
  $(o).css("margin-left", "-"+((o.width-w)/2).toString() + "px"); 
  } 
  else 
  { 
  o.width = img.width; 
  o.height = img.height; 
  }  
 } 
 else 
 { 
  if(img.height > h) 
  { 
  o.height = (img.height*w)/img.width; 
  o.width = w; 
  //o.setAttribute("style", "margin-top:-" + ((o.height-h)/2).toString() + "px"); 
  //$(o).css("style", "margin-top:-" + ((o.height-h)/2).toString() + "px"); 
  $(o).css("margin-top", "-"+((o.height-h)/2).toString() + "px"); 
 } 
  else 
  { 
  o.width = img.width; 
  o.height = img.height; 
  }  
 } 
 } 
}
1

or 


function clipImage(o, w, h){ 
 var img = new Image(); 
 img.src = o.src; 
 if(img.width >0 && img.height>0) 
 { 
 if(img.width/img.height >= w/h) 
 { 
  if(img.width > w) 
  {  
  o.width = (img.width*h)/img.height; 
  o.height = h; 
  //o.setAttribute("style", "marginLeft:-" + ((o.width-w)/2).toString() + "px"); 
  $(o).css("margin-left", "-"+((o.width-w)/2).toString() + "px"); 
  } 
  else 
  { 
  o.width = img.width; 
  o.height = img.height; 
  }  
 } 
 else 
 { 
  if(img.height > h) 
  { 
  o.height = (img.height*w)/img.width; 
  o.width = w; 
  //o.setAttribute("style", "margin-top:-" + ((o.height-h)/2).toString() + "px"); 
  //$(o).css("style", "margin-top:-" + ((o.height-h)/2).toString() + "px"); 
  $(o).css("margin-top", "-"+((o.height-h)/2).toString() + "px"); 
 } 
  else 
  { 
  o.width = img.width; 
  o.height = img.height; 
  }  
 } 
 } 
}
2

8. Judge whether email format is correct 


function chekemail(temail){ 
 var pattern = /^[\w]{1}[\w\.\-_]*@[\w]{1}[\w\-_\.]*\.[\w]{2,4}$/i; 
 if(pattern.test(temail)){return true;}else{return false;} 
}

9. Comprehensively judge user name (length, English field, etc.) 


function clipImage(o, w, h){ 
 var img = new Image(); 
 img.src = o.src; 
 if(img.width >0 && img.height>0) 
 { 
 if(img.width/img.height >= w/h) 
 { 
  if(img.width > w) 
  {  
  o.width = (img.width*h)/img.height; 
  o.height = h; 
  //o.setAttribute("style", "marginLeft:-" + ((o.width-w)/2).toString() + "px"); 
  $(o).css("margin-left", "-"+((o.width-w)/2).toString() + "px"); 
  } 
  else 
  { 
  o.width = img.width; 
  o.height = img.height; 
  }  
 } 
 else 
 { 
  if(img.height > h) 
  { 
  o.height = (img.height*w)/img.width; 
  o.width = w; 
  //o.setAttribute("style", "margin-top:-" + ((o.height-h)/2).toString() + "px"); 
  //$(o).css("style", "margin-top:-" + ((o.height-h)/2).toString() + "px"); 
  $(o).css("margin-top", "-"+((o.height-h)/2).toString() + "px"); 
 } 
  else 
  { 
  o.width = img.width; 
  o.height = img.height; 
  }  
 } 
 } 
}
4

10. News rolling 


function clipImage(o, w, h){ 
 var img = new Image(); 
 img.src = o.src; 
 if(img.width >0 && img.height>0) 
 { 
 if(img.width/img.height >= w/h) 
 { 
  if(img.width > w) 
  {  
  o.width = (img.width*h)/img.height; 
  o.height = h; 
  //o.setAttribute("style", "marginLeft:-" + ((o.width-w)/2).toString() + "px"); 
  $(o).css("margin-left", "-"+((o.width-w)/2).toString() + "px"); 
  } 
  else 
  { 
  o.width = img.width; 
  o.height = img.height; 
  }  
 } 
 else 
 { 
  if(img.height > h) 
  { 
  o.height = (img.height*w)/img.width; 
  o.width = w; 
  //o.setAttribute("style", "margin-top:-" + ((o.height-h)/2).toString() + "px"); 
  //$(o).css("style", "margin-top:-" + ((o.height-h)/2).toString() + "px"); 
  $(o).css("margin-top", "-"+((o.height-h)/2).toString() + "px"); 
 } 
  else 
  { 
  o.width = img.width; 
  o.height = img.height; 
  }  
 } 
 } 
}
5

Java code 


function clipImage(o, w, h){ 
 var img = new Image(); 
 img.src = o.src; 
 if(img.width >0 && img.height>0) 
 { 
 if(img.width/img.height >= w/h) 
 { 
  if(img.width > w) 
  {  
  o.width = (img.width*h)/img.height; 
  o.height = h; 
  //o.setAttribute("style", "marginLeft:-" + ((o.width-w)/2).toString() + "px"); 
  $(o).css("margin-left", "-"+((o.width-w)/2).toString() + "px"); 
  } 
  else 
  { 
  o.width = img.width; 
  o.height = img.height; 
  }  
 } 
 else 
 { 
  if(img.height > h) 
  { 
  o.height = (img.height*w)/img.width; 
  o.width = w; 
  //o.setAttribute("style", "margin-top:-" + ((o.height-h)/2).toString() + "px"); 
  //$(o).css("style", "margin-top:-" + ((o.height-h)/2).toString() + "px"); 
  $(o).css("margin-top", "-"+((o.height-h)/2).toString() + "px"); 
 } 
  else 
  { 
  o.width = img.width; 
  o.height = img.height; 
  }  
 } 
 } 
}
6

11. Only positive integers are allowed (used by shopping cart) 


function clipImage(o, w, h){ 
 var img = new Image(); 
 img.src = o.src; 
 if(img.width >0 && img.height>0) 
 { 
 if(img.width/img.height >= w/h) 
 { 
  if(img.width > w) 
  {  
  o.width = (img.width*h)/img.height; 
  o.height = h; 
  //o.setAttribute("style", "marginLeft:-" + ((o.width-w)/2).toString() + "px"); 
  $(o).css("margin-left", "-"+((o.width-w)/2).toString() + "px"); 
  } 
  else 
  { 
  o.width = img.width; 
  o.height = img.height; 
  }  
 } 
 else 
 { 
  if(img.height > h) 
  { 
  o.height = (img.height*w)/img.width; 
  o.width = w; 
  //o.setAttribute("style", "margin-top:-" + ((o.height-h)/2).toString() + "px"); 
  //$(o).css("style", "margin-top:-" + ((o.height-h)/2).toString() + "px"); 
  $(o).css("margin-top", "-"+((o.height-h)/2).toString() + "px"); 
 } 
  else 
  { 
  o.width = img.width; 
  o.height = img.height; 
  }  
 } 
 } 
}
7

Or a positive number 


<script language="JavaScript" type="text/javascript"> 
 function clearNoNum(obj) 
 { 
 // Let's replace everything that's not a number, except the sum of the Numbers . 
 objobj.value = obj.value.replace(/[^\d.]/g,""); 
 // Must be regulated 1 It's a number, not a number . 
 objobj.value = obj.value.replace(/^\./g,""); 
 // Make sure that only appear 1 a . There are no multiple . 
 objobj.value = obj.value.replace(/\.{2,}/g,"."); 
 // ensure . Only appear 1 Times, but not more than twice  
 objobj.value = obj.value.replace(".","$#$").replace(/\./g,"").replace("$#$","."); 
 } 
</script>

Text boxes where only Numbers and decimal points can be entered: < input id="input1" onkeyup="clearNoNum(this)" >
12. Convert strings to Numbers 


function clipImage(o, w, h){ 
 var img = new Image(); 
 img.src = o.src; 
 if(img.width >0 && img.height>0) 
 { 
 if(img.width/img.height >= w/h) 
 { 
  if(img.width > w) 
  {  
  o.width = (img.width*h)/img.height; 
  o.height = h; 
  //o.setAttribute("style", "marginLeft:-" + ((o.width-w)/2).toString() + "px"); 
  $(o).css("margin-left", "-"+((o.width-w)/2).toString() + "px"); 
  } 
  else 
  { 
  o.width = img.width; 
  o.height = img.height; 
  }  
 } 
 else 
 { 
  if(img.height > h) 
  { 
  o.height = (img.height*w)/img.width; 
  o.width = w; 
  //o.setAttribute("style", "margin-top:-" + ((o.height-h)/2).toString() + "px"); 
  //$(o).css("style", "margin-top:-" + ((o.height-h)/2).toString() + "px"); 
  $(o).css("margin-top", "-"+((o.height-h)/2).toString() + "px"); 
 } 
  else 
  { 
  o.width = img.width; 
  o.height = img.height; 
  }  
 } 
 } 
}
9

13. Determine the file format (get the file suffix) 


//  Usage: get_ext(this,'img'); 
 
function get_ext(name){ 
 var pos = name.lastIndexOf('.'); 
 var extname = name.substring(pos,name.length) // like: str.split('.') 
 var lastname = extname.toLowerCase(); 
 
 if (lastname !='.jpg' && lastname !='.gif' && lastname !='.png' && lastname !='.bmp'){ 
  return lastname; 
 }else{ 
  return name; 
 } 
 } 
}

14. Intercept the string 


//  A simple type  
 
<script type="text/javascript"> 
 
var str="Hello world!" 
document.write(str.substr(3,7)) 
 
</script> 
 
//  As a result,  lo worl 
 
 
//  Complex type (Chinese or Chinese/English mixed interception)  
 
<script> 
// Truncated string   Contains Chinese processing  
//( string , The length of the , increase ...) 
function subString(str, len, hasDot) 
{ 
 var newLength = 0; 
 var newStr = ""; 
 var chineseRegex = /[^\x00-\xff]/g; 
 var singleChar = ""; 
 var strLength = str.replace(chineseRegex,"**").length; 
 for(var i = 0;i < strLength;i++) 
 { 
 singleChar = str.charAt(i).toString(); 
 if(singleChar.match(chineseRegex) != null) 
 { 
  newLength += 2; 
 } 
 else 
 { 
  newLength++; 
 } 
 if(newLength > len) 
 { 
  break; 
 } 
 newStr += singleChar; 
 } 
 
 if(hasDot && strLength > len) 
 { 
 newStr += "..."; 
 } 
 return newStr; 
} 
 
document.write(subString(" hello this is a test!",10,1)); //  The parameters are in order   String,   Truncated length   and   Whether to display ellipses  
</script>

15. Split the string 


<script type="text/javascript"> 
 
var str = 'this_is_a_test_!'; 
var arr = str.split('_'); 
 
document.write(arr + "<br />"); //  List all  
document.write(arr[0] + "<br />"); //  Take a single  
 
</script>

Above are the common javascript functions compiled by this site for you, I hope it will be helpful for you to learn, and then there are more common javascript functions to share with you, continue to follow.

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